Glossary

arcing

a discharge of electricity across a gap

acceleration

rate at which speed increases

bus

an electrical conductor

compare

look at for differences

cranking

rotation of the engine by the starter motor

circuit

connected electric components

deactivate

stop a function

deceleration

rate at which speed decreases

de-energized

power off

energized

power on

failsafe

circuit that gives protection

hertz

cycles per second

hunt

speed changes

hydra-mechanical

hydraulically controlled mechanical action

inversely

the opposite of directly

isochronous

desired engine speed does not change because of a change in load

jumper

electrical connection

kilowatt

measure of electric power

overspeed

engine speed higher than rated speed

override

cause normal electrical signals to be canceled

nonparallel

single

paralleled

electrically connected together to drive a common load

paralleling

all positive poles are connected to one conducter and all negative poles are connected to another conductor

proportion

a ratio

proportional

two factors that have a constant ratio

potentiometer

electric component that has variable resistance

ramp

circuit that controls movement from one level to another

response

time and stability characteristic of a change in output

sensing phasing

measurement and comparison of output with other units in the system

short

any connection between two or more electrical components that is not desired

shielding

steel braid for protection of a wire

sharing

two or more engines used to drive a common load

speed droop

no load engine rpm minus full load rpm

standby

ready for use during an emergency

transfer

change from one to another

Woodward PSG Governors

SCHEMATIC OF LATEST PSG GOVERNOR
1. Return spring. 2. Output shaft. 3. Output shaft lever. 4. Strut assembly. 5. Speeder spring. 6. Power piston. 7. Flyweights. 8. Needle valve. 9. Thrust bearing. 10. Pilot valve compensating land. 11. Buffer piston. 12. Pilot valve. 13. Pilot valve bushing. 14. Control ports. A. Chamber. B. Chamber.

Introduction

The Woodward PSG (Pressure compensated Simple Governor) can operate as an isochronous or a speed droop type governor. It uses engine lubrication oil, increased to a pressure of 175 psi (1200 kPa) by a gear type pump inside the governor, to give hydra/mechanical speed control.

Pilot Valve Operation

The fuel injection pump camshaft drives a governor drive unit. This unit turns pilot valve bushing (13) clockwise as seen from the drive unit end of the governor. The pilot valve bushing is connected to a spring driven ballhead. Flyweights (7) are fastened to the ballhead by pivot pins. The centrifugal force caused by the rotation of the pilot valve bushing causes the flyweights to pivot out. This action of the flyweights changes the centrifugal force to axial force against speeder spring (5). There is a thrust bearing (9) between the toes of the flyweights and the seat for the speeder spring. Pilot valve (12) is fastened to the seat for the speeder spring. Movement of the pilot valve is controlled by the action of the flyweights against the force of the speeder spring.

The engine is at the governed (desired) rpm when the axial force of the flyweights is the same as the force of compression in the speeder spring. The flyweights will be in the position shown. Control ports (14) will be closed by the pilot valve.

Fuel Increase

When the force of compression in the speeder spring increases (operator increases desired rpm) or the axial force of the flyweights decreases (load on the engine increases) the pilot valve will move in the direction of the drive unit. This opens control ports (14). Pressure oil flows through a passage in the base to chamber (B). The increased pressure in chamber (B) causes power piston (6) to move. The power piston pushes strut assembly (4), that is connected to output shaft lever (3). The action of the output shaft lever causes clockwise rotation of output shaft (2). This moves fuel control linkage (15) in the FUEL ON direction.

PSG GOVERNOR INSTALLED
2. Output shaft. 15. Fuel control linkage.

As the power piston moves in the direction of return spring (1) the volume of chamber (A) increases. The pressure in chamber (A) decreases. This pulls the oil from the chamber inside the power piston, above buffer piston (11) into chamber (A). As the oil moves out from above buffer piston (11) to fill chamber (A) the buffer piston moves up in the bore of the power piston. Chambers (A and B) are connected respectively to the chambers above and below the pilot valve compensating land (10). The pressure difference felt by the pilot valve compensating land adds to the axial force of the flyweights to move the pilot valve up and close the control ports. When the flow of pressure oil to chamber (B) stops so does the movement of the fuel control linkage.

Fuel Decrease

When the force of compression in the speeder spring decreases (operator decreases desired rpm) or the axial force of the flyweights increases (load on the engine decreases) the pilot valve will move in the direction of speeder spring (5). This opens control ports (14). Oil from chamber (B) and pressure oil from the pump will dump through the end of the pilot valve bushing. The decreased pressure in chamber (B) will let the power piston move in the direction of the drive unit. Return spring (1) pushes against strut assembly (4). This moves output shaft lever (3). The action of the output shaft lever causes counterclockwise rotation of output shaft (2). This moves fuel control linkage (15) in the FUEL OFF direction.

EARLIER PSG GOVERNOR
6. Power piston. 8. Needle valve. 10. Pilot valve compensating land. 11. Buffer piston. 14. Control ports. A. Chamber. B. Chamber.

As power piston (6) moves in the direction of the drive unit the volume of chamber (A) decreases. This pushes the oil in chamber (A) into the chamber above buffer piston (11). As the oil from chamber (A) flows into the power piston it moves the buffer piston down in the bore of the power piston. The pressure at chamber (A) is more than the pressure at chamber (B). Chambers (A and B) are connected respectively to chambers above and below the pilot valve compensating land (10). The pressure difference felt by the pilot valve compensating land adds to the force of the speeder spring to move the pilot valve down and close the control ports. When the flow of oil from chamber (B) stops so does the movement of the fuel control linkage.

Hunting

There is a moment between the time the fuel control linkage stops its movement and the time the engine actually stops its increases or decrease of rpm. During this moment there is a change in two forces on the pilot valve, the pressure difference at the pilot valve compensating land and the axial force of the flyweights.

The axial force of the flyweights changes until the engine stops its increase or decrease of rpm. The pressure difference at the pilot valve compensating land changes until the buffer piston returns to its original position. A needle valve (8) in a passage between space (A) and (B) controls the rate at which the pressure difference changes. The pressure difference makes compensation for the axial force of the flyweights until the engine stops it increase or decrease of rpm. If the force on the pilot valve compensating land plus the axial force of the flyweights is not equal to the force of the speeder spring the pilot valve will move. This movement is known as hunting (movement of the pilot valve that is not the result of a change in load or desired rpm of the engine).

The governor will hunt each time the engine actually stops its increase or decrease of rpm at any other rpm than that desired. The governor will hunt more after a rapid or large change of load or desired rpm than after a gradual or small change.

PSG GOVERNOR
8. Needle valve.

NOTE: The Woodward PSG Governor is removed from the engine to show the needle valve (8). When the governor is installed on the engine, the needle valve (8) is between the governor and the cylinder block.

Speed Adjustment

The earliest PSG governors use a screw (1). When the screw is turned clockwise it pushes the link assembly (2) down. This causes an increase in the force of speeder spring (3) and pilot valve (4) will move down. See PILOT VALVE OPERATION. The engine will increase speed until it gets to the desired rpm. When the screw is turned counterclockwise the link assembly moves up. This causes a decrease in the force of the speeder spring and the pilot valve will move up. The engine will decrease speed until it gets to the desired rpm.

Later PSG governors use a clutch assembly (6) driven by a 110V AC/DC or 24V DC reversible synchronizing motor (5) to move link assembly (7) up or down. The clutch assembly protects the motor if the adjustment is run against the stops. The motor is controlled by a switch that is remotely mounted. The clutch assembly can be turned manually if necessary.

EARLIEST PSG GOVERNOR
1. Screw. 2. Link assembly. 3. Speeder spring. 4. Pilot valve.

LATER PSG GOVERNOR
5. Synchronizing motor. 6. Clutch assembly. 7. Link assembly.

Speed Droop

EARLIER PSG GOVERNOR
1. Bracket. 2. Pivot pin. 3. Output shafts.

Speed droop is the difference between no load rpm and full load rpm. This difference in rpm divided by the full load rpm and multiplied by 100 is the percent of speed droop.

The speed droop of the PSG governor can be adjusted. The governor is isochronous when it is adjusted so that the no load and full load rpm is the same. Speed droop permits load division between two or more engines that drive generators connected in parallel or generators connected to a single shaft.

Speed droop adjustment on PSG governors is made by movement of pivot pin (2). When the pivot pin is put in alignment with the output shafts, movement of the output shaft lever will not change the force of the speeder spring. When the force of the speeder spring is kept constant the desired rpm will be kept constant. See PILOT VALVE OPERATION. When the pivot pin is moved out of alignment with the output shafts, movement of the output shaft lever will change the force of the speeder spring proportional to the load on the engine. When the force of the speeder spring is changed the desired rpm of the engine will change.

On earlier PSG governors the cover must be removed to adjust the speed droop. Later models have an adjustment lever outside the governor connected to pivot pin (2) by link (4).

LATER PSG GOVERNOR
2. Pivot pin. 4. Link.

Shutoff And Alarm Systems

Alarm Contactor System

WIRING SCHEMATIC (Typical Example)
1. Oil pressure switch (switch with manual override shown). 2. Water temperature contactor. 3. Source voltage. 4. Toggle switch (optional). 5. Alarm. 6. Signal lights.

If the oil pressure is too low or the water temperature is too high this system will activate alarm (5) and signal lights (6).

Show/hide table

NOTICE
When the alarm and signal lights activate stop the engine immediately. This will help prevent damage to the engine from heat or not enough lubrication. Find and correct the problem that caused the alarm and signal lights to activate.

Before the engine is started it will be necessary to override the oil pressure switch (1) or the alarm will activate. This is done by either a manual override button on the oil pressure switch or toggle switch (4). Oil pressure will return the manual override button to the run position. The toggle switch must be manually closed when the engine has oil pressure.

Water Temperature And Oil Pressure Shutoff System

WIRING SCHEMATIC (Typical Example)
1. Oil pressure switch (switch with manual override shown). 2. Water temperature contactor. 3. Oil pressure (time delay) or fuel pressure switch. 4. Shutoff solenoid. 5. Terminal block. 6. Diode assembly. 7. Starter. 8. Battery.

If the oil pressure is too low or the water temperature is too high this system will activate shutoff solenoid (4). The solenoid is connected to the fuel control shaft by linkage. When it is activated it will move to stop the flow of fuel to the engine. The engine will stop.

Show/hide table

NOTICE
Find the correct the problem that caused the engine to stop. This will help prevent damage to the engine from heat or not enough lubrication.

Before the engine can be started it will be necessary to push the manual override button on oil pressure switch (1). Oil pressure will return the manual override button to the run position.

Diode assembly (6) is used to stop arcing, for protection of the system.

Oil pressure delay or fuel pressure switch (3) is used to prevent discharge of battery (8) through the solenoid when the engine is stopped. The optional grounds to engine shown are used with grounded systems only.

Electronic Overspeed Shutoff System

WIRING SCHEMATIC (Typical Example)
1. Shutoff solenoid. 2. Diode assembly. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Magnetic pickup. 6. Terminal block. 7. Starter. 8. Battery.

Magnetic pickup (5) sends a voltage to overspeed switch (4). The frequency of this voltage tells the overspeed switch the speed of the engine. If the speed of the engine gets too high the overspeed switch sends a signal to activate shutoff solenoid (1).

The shutoff solenoid is connected to the fuel control shaft by linkage. When it is activated it will move to stop the flow of fuel to the engine.

Show/hide table

NOTICE
Find and correct the problem that caused the engine to overspeed. This will help prevent damage to the engine.

After an overspeed shutdown the overspeed switch must be reset before the engine can start.

Diode assembly (2) is used to stop arcing, for protection of the system.

The optional grounds to the engine shown are used with grounded systems only.

An oil pressure (time delay) or fuel pressure switch (3) is used to prevent discharge of battery (8) through the solenoid when the engine is stopped. The electronic overspeed switch can be connected to the battery constantly because it uses less than 20 MA of current when the engine is stopped.

Water Temperature, Oil Pressure And Electronic Overspeed Shutoff System

WIRING SCHEMATIC (Typical Example)
1. Oil pressure switch (switch with manual override shown). 2. Water temperature contactor. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Shutoff solenoid. 6. Diode assembly. 7. Magnetic pickup. 8. Terminal block. 9. Starter. 10. Battery.

The shutoff solenoid can be activated by oil pressure switch (1), water temperature contactor (2) or overspeed switch (4). See WATER TEMPERATURE AND OIL PRESSURE SHUTOFF SYSTEM and ELECTRONIC OVERSPEED SHUTOFF SYSTEM.

Mechanical Overspeed Shutoff System

WIRING SCHEMATIC (Typical Example)
1. Shutoff solenoid. 2. Diode assembly. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Terminal block. 6. Starter. 7. Battery.

The mechanical overspeed switch (4) is fastened to the tachometer drive on the engine. Wires connect the switch to the fuel shutoff solenoid. If the speed of the engine gets too high the overspeed switch sends a signal to activate shutoff solenoid (1).

The shutoff solenoid is connected to the fuel control shaft by linkage. When it is activated it will move to stop the flow of fuel to the engine.

Show/hide table

NOTICE
Find and correct the problem that caused the engine to overspeed. This will help prevent damage to the engine.

After an overspeed shutdown the overspeed switch must be reset before the engine can start.

Diode assembly (2) is used to stop arcing, for protection of the system.

The optional grounds to the engine shown are used with grounded systems only.

An oil pressure (time delay) or fuel pressure switch (3) is used to prevent discharge of battery (7) through the solenoid when the engine is stopped.

Water Temperature, Oil Pressure And Mechanical Overspeed Shutoff System

WIRING SCHEMATIC (Typical Example)
1. Oil pressure switch (switch with manual override shown). 2. Water temperature contactor. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Shutoff solenoid. 6. Diode assembly. 7. Terminal block. 8. Starter. 9. Battery.

The shutoff solenoid can be activated by oil pressure switch (1), water temperature contactor (2) or overspeed switch (4). See WATER TEMPERATURE AND OIL PRESSURE SHUTOFF SYSTEM and MECHANICAL OVERSPEED SHUTOFF SYSTEM.

Mechanical Oil Pressure And Water Temperature Shutoff

MECHANICAL SHUTOFF GROUP
1. Tee. 2. Oil line. 3. Shutoff housing. 4. Oil line. 5. Control valve. 6. To timing gear cover.

The oil pressure shutoff housing (3) is fastened to the governor. Lever (12) is connected by a shaft to shutoff levers (13) and (14).

OIL PRESSURE SHUTOFF
3. Shutoff housing. 7. Cover. 8. Diaphragm. 9. Plunger. 10. Spring. 11. Stud. 12. Lever.

NORMAL OPERATING CONDITIONS
9. Plunger. 13. Lever. 14. Lever.

Before the engine can be started, lever (12) is used to turn spring loaded lever (13) away from the shutoff position. With lever (13) in this position the engine can be started.

When the engine starts, pressure oil flows through cover (7) moving plunger (9) into position to hold lever (13). As long as the engine has enough oil pressure the fuel control shaft can be controlled by the governor.

If the oil pressure gets too low, spring (10) moves plunger (9) away from lever (13). Lever (13) returns to the shutoff position and causes the engine to stop.

NOTE: With lever (13) held in the normal operating position as shown, lever (14) is used to shutdown the engine if necessary. This can be done manually or with a shutoff solenoid if so equipped.

Show/hide table

NOTICE
Find and correct the problem that caused the engine to stop. This will help prevent damage to the engine from not enough lubrication.

Water temperature shutoff (5) is a control valve for the oil pressure shutoff.

When the water temperature becomes too high thermostat assembly (17) causes stem (16) to move ball (18) off of its seat. Pressure oil at inlet port (15) will go through the valve and drain into the engine crankcase. This will cause the oil pressure to decrease. The oil pressure shutoff will activate and stop the engine.

Show/hide table

NOTICE
Find and correct the problem that caused the engine to stop. This will help prevent damage to the engine from too much heat.

TEMPERATURE SHUTOFF
15. Inlet port. 16. Stem. 17. Thermostat assembly. 18. Ball.

Shutoff And Alarm System Components

Oil Pressure Switch

Micro Switch Type

The oil pressure switch is used to give protection to the engine from damage because of low oil pressure. When oil pressure lowers to the pressure specifications of the switch, the switch closes and activates the fuel shutoff solenoid.

On automatic start/stop installations, this switch closes to remove the starting system from the circuit when the engine is running with normal oil pressure.

The switch for oil pressure can be connected in a warning system for indication of low oil pressure with a light or horn.

As pressure of the oil in bellows (6) becomes higher, arm (4) is moved against the force of spring (3). When projection (10) of arm (4) makes contact with arm (9), pressure in the bellows moves both arms. This also moves button (8) of the micro switch to activate the micro switch.

OIL PRESSURE SWITCH (Micro Switch Type)
1. Locknut. 2. Adjustment screw. 3. Spring. 4. Arm. 5. Spring. 6. Bellows. 7. Latch plate. 8. Button for micro switch. 9. Arm. 10. Projection of arm.

Some of these switches have a "Set For Start" button. When the button is pushed in, the micro switch is in the START position. This is done because latch plate (7) holds arm (9) against button (8) of the micro switch and the switch operates as if the oil pressure was normal. When the engine is started, pressure oil flows into bellows (6). The bellows move arm (4) into contact with latch plate (7). The latch plate releases the "Set For Start" button and spring (5) moves it to the RUN position. This puts the switch in a ready to operate condition.

Earlier Type Switch

Early type switches for oil pressure have a control knob (1). The knob must be turned (reset) every time the engine is stopped. Turn the knob counterclockwise to the OFF position before the engine is started. The knob will move to the RUN position when the oil pressure is normal.

OIL PRESSURE SWITCH (Earlier Type)
1. Control knob.

Pressure Switch With Time Delay

PRESSURE SWITCH WITH TIME DELAY
1. Damper. 2. Pressure switch. 3. Valve.

The pressure switch with time delay has three main parts. The damper (1) is a reservoir for air and oil. The pressure switch (2) is a switch which activates from engine oil pressure. The valve (3) is a check valve with an orifice.

When the engine starts running the oil pressure in the engine increases. The oil goes through the valve (3) easily because the ball is off its seat from flow in that direction. There is air in the damper (1). The oil through the valve (3) goes into the damper (1). The oil puts compression on the air in the damper (1) until the pressure in the damper (1) is equal to engine oil pressure. This action takes a very short time. As the pressure in the damper (1) increases, the pressure switch (2) has the same pressure. At the correct pressure, the pressure (2) switch closes.

When the oil pressure in the engine decreases, there is a different set of conditions. The oil pressure in the engine is lower than the pressure in the damper (1). The high pressure in the damper (1) pushes oil out of the damper (1). The ball is on its seat. The pressure holds it there. Now the oil can only get out through the orifice. The orifice is a very small hole which is drilled through the body of the valve (3). It connects the oil in the damper (1) with the oil in the engine. The orifice is a restriction to the flow of oil out of the damper (1). The pressure in damper (1) takes a longer time to decrease than the oil pressure in the engine. This difference is the delay. When the engine is stopped under normal conditions, the delay is a minimum of approximately 4 seconds after the engine stops turning.

PRESSURE SWITCH WITH TIME DELAY INSTALLED
1. Damper. 2. Pressure switch. 3. Valve.

NOTE: Damper (1) must be installed vertically as shown to work correctly.

Pressure Switch

These type pressure switches are used for several purposes and are available with different specifications. They are used in the oil system and in the fuel system. One use of the switch is to open the circuit between the battery and the fuel shutoff solenoid after the oil pressure is below the pressure specifications of the switch. It also closes when the engine starts.

PRESSURE SWITCH

Another use of the switch is to close and activate the battery charging circuit when the pressure is above the pressure specification of the switch. It also disconnects the circuit when the engine is stopped.

Some switches of this type have three terminal connections. They are used to do two operations with one switch. They open one circuit and close another with the single switch.

Water Temperature Contactor Switch

The contactor switch for water temperature is installed in the water manifold. No adjustment to the temperature range of the contactor can be made. The element feels the temperature of the coolant and then operates the micro switch in the contactor when the coolant temperature is too high, the element must be in contact with the coolant to operate correctly. If the cause for the engine being too hot is because of low coolant level or no coolant, the contactor switch will not operate.

The contactor switch is connected to the fuel shutoff solenoid to stop the engine. The switch can also be connected to an alarm system. When the temperature of the coolant lowers to the operating range, the contactor switch opens automatically.

WATER TEMPERATURE CONTACTOR SWITCH

Circuit Breaker

The circuit breaker gives protection to an electrical circuit. Circuit breakers are rated as to how much current they will permit to flow. If the current in a circuit gets too high it will cause heat in disc (3). Heat will cause distortion of the disc and contacts (2) will open. No current will flow in the circuit.

Show/hide table

NOTICE
Find and correct the problem that caused the circuit breaker to open. This will help prevent damage to the circuit components from too much current.

An open circuit breaker will close (reset) automatically when it becomes cooler.

CIRCUIT BREAKER SCHEMATIC
1. Disc in open position. 2. Contacts. 3. Disc. 4. Circuit terminals.

Shutoff Solenoid

A shutoff solenoid changes electrical input into mechanical output. It is used to move the fuel control shaft to a no fuel position. This stops the engine.

The shutoff solenoid can be activated by any one of many sources. The most usual are: water temperature contactor, oil pressure switch, overspeed switch (electronic or mechanical) and remote manual control switch.

ACTIVATE TO SHUTOFF SOLENOID

When activated, the activate to shutoff solenoid moves the fuel control shaft to the fuel off position.

ACTIVATE TO SHUTOFF SOLENOID INSTALLED

ACTIVATE TO RUN SOLENOID

ACTIVATE TO RUN SOLENOID INSTALLED

When shut off, the activate to run shutoff solenoid moves the fuel control shaft to the fuel off position.

Mechanical Overspeed Switch

The overspeed switch is installed on the tachometer drive shaft on the fuel injection pump. The switch activates when the engine speed is equal to the overspeed setting. When the overspeed switch has activated, the contacts do not automatically return to their normal positions. The reset button (1) must be pushed by the operator to make the switch contacts return to their normal positions. The usual setting for the overspeed switch is 18% higher than the rated speed of the engine.

MECHANICAL OVERSPEED SWITCH
1. Button.

Some overspeed switches also have underspeed contacts. These contacts close at approximately 600 rpm as the engine speed increases. The underspeed setting is not adjustable.

Electronic Speed Switch

The electronic speed switch (dual speed switch) activates the shutoff solenoid when the engine speed gets approximately 18% higher than the rated full load speed of the engine. It also causes the starter motor pinion to move away from the flywheel.

NOTE: Some earlier electronic speed switches do not have the crank disconnect.

The electronic speed switch makes a comparison between the output frequency of magnetic pickup (2) and the setting of the electronic speed switch. When they are equal, the normally open contacts in the electronic speed switch close. On earlier models handle (1) moves to the overspeed position. On later models lamp (4) will go on. The switch also has a fail safe circuit that will cause the engine to shutdown if there is an open in the magnetic pickup circuit.

When the engine is stopped by the earlier electronic speed switch it will be necessary to move handle (1) to the run position before the engine can be started. On later model switches push reset button (3).

ELECTRONIC SPEED SWITCH (EARLIER)
1. Handle. 2. Magnetic pickup.

MAGNETIC PICKUP INSTALLED
2. Magnetic pickup.

ELECTRONIC SPEED SWITCH (LATER)
3. Reset button. 4. Lamp.

Power Take-Off Clutches

POWER TAKE-OFF CLUTCH (Typical Illustration)
1. Ring. 2. Driven discs. 3. Link assemblies. 4. Lever. 5. Key. 6. Collar assembly. 7. Nut. 8. Yoke assembly. 9. Hub. 10. Plates. 11. Output shaft.

Power take-off clutches (PTO's) are used to send power from the engine to accessory components. For example, a PTO can be used to drive an air compressor or a water pump.

The PTO is driven by a ring (1) that has spline teeth around the inside diameter. The ring can be connected to the front or rear of the engine crankshaft by an adapter.

NOTE: On some PTO's located at the rear of the engine, ring (1) is a part of the flywheel.

The spline teeth on the ring engage with the spline teeth on the outside diameter of driven discs (2). When lever (4) is moved to the ENGAGED position, yoke assembly (8) moves collar assembly (6) in the direction of the engine. The collar assembly is connected to four link assemblies (3). The action of the link assemblies will hold the faces of driven discs (2), drive plates (10) and hub (9) tight together. Friction between these faces permits the flow of torque from ring (1), through driven discs (2), to plates (10) and hub (9). Spline teeth on the inside diameter of the plates drive the hub. The hub is held in position on the output shaft (11) by a taper, nut (7) and key (5).

NOTE: A PTO can have from one to three driven discs (2) with a respective number of plates.

When lever (4) is moved to the NOT ENGAGED position, yoke assembly (8) moves collar assembly (6) to the left. The movement of the collar assembly will release link assemblies (3). With the link assemblies released there will not be enough friction between the faces of the clutch assembly to permit a flow of torque.

Automatic Start/Stop System (Non-Package Generator Sets)

AUTOMATIC START/STOP SYSTEM SCHEMATIC (Hydraulic Governor)
1. Magnetic pickup. 2. Starter motor and solenoid. 3. Shutoff solenoid. 4. Oil pressure switch. 5. Water temperature switch. 6. Oil pressure time delay switch. 7. Electronic overspeed switch. 8. Battery. 9. Initiating relay (IR). 10. Shutdown relay (SR). 11. Auxiliary relay (AR). 12. Overcrank timer (OCT). 13. Time delay relay (TD). 14. ON/OFF/STOP switch (SW2). 15. AUTOMATIC/MANUAL switch (SW1). 16. Terminal board (TS1).

An automatic start/stop system is used when a standby electric set has to give power to a system if the normal (commercial) power supply has a failure. There are three main sections in the system. They are: the automatic transfer switch, the cranking panel and the electric set.

Automatic Transfer Switch

The automatic transfer switch normally connects the 3-phase normal (commercial) power supply to the load. When the commercial power supply has a failure the switch will transfer the load to the standby electric set. The transfer switch will not transfer the load from commercial to emergency power until the emergency power gets to the rated voltage and frequency. The reason for this is the solenoid that causes the transfer of power operates on the voltage from the standby electric set. When the normal power returns to the rated voltage and frequency and the time delay (if so equipped) is over, the transfer switch will return the load to the normal power supply.

AUTOMATIC TRANSFER SWITCH

Cranking Panel

The main function of the cranking panel is to control the start and shutoff of the electric set.

BASIC CRANKING PANEL
1. Indicator light. 2. Manual-Automatic switch. 3. ON-OFF-STOP switch.

LOCKOUT indicator light (1) will activate if, the engine does not start, or if a protection device gives the signal to shutoff during operation.

Switch (2) gives either AUTOMATIC or MANUAL starting. In the diagrams shown later this switch is called SW1. Switch (3) has three positions "ON", "OFF" and "STOP". This switch is called SW2 in the diagrams. Move SW2 (3) to ON and SW1 (2) to MAN to start the engine immediately. Move SW2 (3) to OFF on an electric set in operation to start the shutoff sequence. If the system is equipped with a time delay the engine will not stop immediately. When SW2 (3) is moved to the STOP position the engine stops immediately. The switch must be held in the STOP position until the engine stops. When the switch is released a spring returns it to the OFF position. With SW2 (3) in the ON position and SW1 (2) in the AUTO position the control is ready for standby operation.

There are several attachments that can be ordered for this panel. A description of how each one works and the effect it has on the operation of the standard system is given after the explanations of the standard system.

Electric Set

The components of the electric set are: the engine, the generator, the starting motor, the battery, the shutoff solenoid and signal switches on the engine. The electric set gives emergency power to drive the load.

An explanation of each of the signal components is given in separate topics.

Hydraulic Governor Application

The circuit illustrations that follow are basic schematics. DO NOT use them as complete wiring diagrams.

AR

Auxiliary relay

CB

Circuit breaker

CR

Cranking relay

CT

Cranking terminate relay (part of OS)

D

Diode

IR

Initiating relay

MS

Magnetic switch

OCT

Overcrank timer

OPS

Oil pressure shutdown switch

OPTD

Oil pressure time delay switch

OS

Overspeed shutdown switch

PS

Pinion solenoid

RR

Run relay

RS

Fuel Shutoff Solenoid

SM

Starting motor

SR

Shutdown relay

SW1

Automatic/Manual switch

SW2

On/Off/Stop switch

WT

Water temperature shutdown switch

Automatic Starting Operations

When emergency power is needed, the initiating contactor closes. This energizes the initiating relay and the run relay. The current flow through the initiating relay contacts then energizes the magnetic switch, which energizes the pinion solenoid. The starting motor is now connected to the battery. The starting operation starts. At the same time the overcrank timer is energized and starts to run.

At 600 rpm the cranking terminate relay closes. Oil pressure causes oil pressure shutdown switch (OPS) to activate. The normally closed contacts open and the normally open contacts close. When oil pressure shutdown switch (OPS) activates, the auxiliary relay is energized and current flow to the magnetic switch and pinion solenoid is stopped. The starting operation then stops.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; ENGINE STARTING

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; ENGINE STARTS

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; ENGINE DOES NOT START

If the engine does not start in 30 seconds, the overcrank timer contact closes. This energizes the shutdown relay and the alarm light. The shutdown relay stops current flow to the initiating relay and the run relay. De-energizing the run relay also stops current flow to the auxiliary relay. When the shutdown relay is energized, the magnetic switch and the pinion solenoid are de-energized. The starting operation then stops. The shutdown relay also energizes the shutoff solenoid to move the fuel control shaft to the fuel OFF position. The shutdown relay is energized until switch (SW2) is manually turned to the OFF position.

Automatic Stopping Operations

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; SHUTDOWN BY PROTECTION COMPONENT

When the contacts for any of the shutdown switches close, the shutdown relay and the alarm light are energized. This de-energizes the initiating relay, run relay and auxiliary relay. The shutoff solenoid is energized to move the fuel control shaft to the fuel OFF position. A parallel circuit through the fuel pressure switch and the normally closed contact of the run relay is also completed to the shutoff solenoid. The shutdown relay is energized until switch (SW2) is manually turned to the OFF position.

When commercial power is started again, the initiating contactor opens. This de-energizes the initiating relay, the run relay and the auxiliary relay. Current then goes through the normally closed contact of the run relay to the shutoff solenoid. The shutoff solenoid is energized to move the fuel control shaft to the FUEL OFF position.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; EMERGENCY POWER NOT NEEDED

Manual Starting Operation

CONTROL PANEL CONTROLS IN MANUAL POSITION; ENGINE STARTING

Switch (SW1), in the MANUAL position, removes the initiating contactor from the circuit. In the MANUAL Position the initiating relay and the run relay are energized. This energizes the magnetic switch and the pinion solenoid. The starting motor is now connected to the battery. The starting operation starts. The overcrank timer is not in this circuit, so if the engine does not start, either switch (SW1) or (SW2) must be turned to another position to stop the starting operation. When the engine starts, the magnetic switch and the pinion solenoid are de-energized in the same way they are de-energized when the engine starts in the AUTOMATIC position.

Manual Stopping Operation

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; MANUAL SHUTDOWN

When switch (SW2) is move to the STOP position, current flow is directly to the shutoff solenoid. The shutoff solenoid moves the fuel control shaft to the fuel OFF position. The initiating relay, run relay and auxiliary relay are de-energized. Switch (SW2) must be held in the STOP position until the engine stops.

Attachments For Cranking Panel

Separate Alarm Lights

SEPARATE ALARM LIGHTS

This attachment shows the reason for shutdown.

Cycle Cranking Timer

The cycle cranking timer has a cycle crank module (CC). It permits adjustment of the amount of time that the starting motor operates. It can be set for 30 seconds of constant operation to 5 cycles of 10 seconds of operation with a 10 second delay between each cycle of operation. When the cranking cycles set in the timer are completed, cycle crank module (CC) closes the circuit to the overcrank relay (OCT).

Time Delay Relay

This attachment causes a 2 minute delay in the activation of the shutoff solenoid (RS) when the engine is automatically being stopped because of the return of (commercial) normal power.

The purpose of this time delay is to let the engine cool more slowly after running.

When the (commercial) normal power starts again, the initiating contactor (1) opens. This opens the circuit to the run relay (RR) and initiating relay (IR). The run relay (RR) has normally closed contacts which connect the oil pressure time delay switch (OPTD) with the time delay relay (TD). The oil pressure time delay switch (OPTD) is closed at this time. The time delay relay (TD) starts to measure time. After 2 more minutes of engine operation, the time delay relay (TD) activates. It closes its normally open contacts in the circuit between the oil pressure time delay switch (OPTD) and the shutoff solenoid (RS). Because the oil pressure time delay switch (OPTD) is closed, the circuit is now closed to the shutoff solenoid (RS): The shutoff solenoid (RS) activates. It moves the fuel control shaft to the FUEL OFF position. This makes the engine stop running.

If the (commercial) normal power stops before the engine stops turning, the engine can start running again immediately. This is because the initiating contactor (I) closes again. This closes the circuit to run relay (RR) and initiating relay (IR). The run relay (RR) activates and opens its normally closed contacts in the circuit with the time delay relay (TD). The time delay relay (TD) is now disconnected so it opens its normally open contacts in the circuit with the shutoff solenoid (RS). The shutoff solenoid (RS) releases the fuel in the fuel injection pump. The governor now controls the fuel supply to the engine. The governor gives the engine more fuel to make the speed increase to the correct speed for the engine.

If the initiating contactor (I) closes just as the engine stops turning, the starting motor can activate almost immediately. This is because the oil pressure switch (OPS) is activated by engine oil pressure. When the engine stops running, the oil pressure decreases faster than the engine stops its motion. If the engine does not start running again because of the force of rotation of the flywheel, the engine oil pressure does not increase to activate the oil pressure switch (OPS). If the oil pressure switch (OPS) does not activate, the starting motor (SM) activates when the initiating relay (IR) closes its contacts.

SCHEMATIC OF CONTROL PANEL (SHOWS ALL STANDARD ATTACHMENTS) (ALL COMPONENTS ARE SHOWN IN NORMAL CONDITIONS)

The components are:

WIRING DIAGRAM FOR AUTOMATIC START-STOP SYSTEM (EARLIER)
1. Magnetic switch. 2. Terminals (on electronic speed switch). 3. Magnetic pickup. 4. Flywheel. 5. Circuit breaker. 6. Battery. 7. Starting motor. 8. Oil pressure switch. 9. Pressure switch with time delay. 10. Water temperature contactor. 11. Shutoff solenoid. 12. TS1. 13. Synchronizing motor for Woodward PSG Governor.

WIRING DIAGRAM FOR AUTOMATIC START-STOP SYSTEM (LATER)
1. Magnetic switch. 2. Terminals (on electronic speed switch). 3. Magnetic pickup. 4. Flywheel. 5. Circuit breaker. 6. Battery. 7. Starting motor. 8. Oil pressure switch. 9. Pressure switch with time delay. 10. Water temperature contactor. 11. Shutoff solenoid. 12. TS1. 13. Synchronizing motor for Woodward PSG Governor.

Instrument Panel

WIRING DIAGRAM FOR INSTRUMENT PANEL
1. Light switch. 2. Panel lights. 3. Instrument panel. 4. Ammeter. 5. Oil pressure gauge. 6. Water temperature gauge. 7. Gear oil pressure gauge. 8. Terminal strip. 9. Wire to battery. 10. Oil pressure switch with time delay. 11. Sending unit for oil pressure. 12. Sending unit for water temperature. 13. Sending unit for gear oil pressure.

GAUGES WITH RESISTORS FOR 32 VOLT SYSTEM
1. Resistor. 2. 0-80 psi oil pressure gauge. 3. Resistor. 4. 100°-240° F water temperature gauge. 5. Resistor. 6. 0-300 psi gear oil pressure gauge.

Electrical Gauges And Sending Units

The electrical gauges and sending units operate in electrical balance. Because of this, the voltage and resistance ratings are important to get the correct indications on the gauges. The chart shows components that operate together.

Sending Unit for Water Temperature

SENDING UNIT FOR WATER TEMPERATURE
1. Connection. 2. Bushing. 3. Bulb.

The sending unit for water temperature is an electrical resistance. It changes the value of its resistance according to the temperature which the bulb (3) feels.

The sending unit is in a series circuit with the electrical gauge. When the temperature is high, the resistance is high. This makes the gauge have a high reading.

The sending unit must be in contact with the coolant. If the coolant level is too low because of a sudden loss of coolant while the engine is running or because the level is too low before starting the engine, the sending unit will not work correctly.

Sending Unit for Oil Pressure

SENDING UNIT FOR OIL PRESSURE
1. Connection. 2. Fitting.

The sending unit for oil pressure is an electrical resistance. It has a material which changes electrical resistance according to pressure which it feels.

The sending unit for oil pressure is in a series circuit with the electrical gauge. As the pressure on the sending unit changes, the reading on the gauge changes in the same way.

Electric Hour Meter

WIRING DIAGRAM FOR ELECTRIC HOUR METER
1. Electrical hour meter. 2. Pressure switch. 3. To alternator or battery.

The electric hour meter (1) measures the clock hours that the engine operates. The electric hour meter (1) activates when the pressure switch (2) closes. The pressure switch (2) closes the circuit from the positive terminal on the alternator or battery when the engine oil pressure is above approximately 6 psi (40 kPa).

Wiring Diagrams

TACHOMETER WIRING DIAGRAM (EARLIER)
1. Tachometer. 2. "Y" connecting harness (used only for engines with two tachometers). 3. Cable and socket assembly. 4. Tachometer sending unit.

TACHOMETER WIRING DIAGRAM (LATER)
1. Tachometer. 2. Sending Unit. 3. TS1.

CHARGING SYSTEM
1. Shunt. 2. Regulator. 3. Battery. 4. Alternator.

Troubleshooting

Troubleshooting can be difficult. On the following pages there is a list of possible problems. To make a repair to a problem, make reference to the cause and correction.

This list of problems, causes, and corrections, will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendations in the list. Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list can not give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.

1. Contactor Switch for Water Temperature Does Not Activate Shutoff Solenoid.

2. Contactor Switch for Water Temperature Activates Shutoff Solenoid at Wrong Temperature.

3. Contactor Switch for Oil Pressure Fails to Activate Shutoff Solenoid.

4. Contactor Switch for Overspeed Fails to Activate Shutoff Solenoid.

5. Contactor Switch for Overspeed Activates Shutoff Solenoid at Wrong Speed.

6. Shutoff Solenoid Fails to Stop Engine.

7. Shutoff Solenoid Prevents Engine Start.

8. Clutch Will Not Engage (Slips), Heats or Lever Moves to Released Position.

9. Clutch Shaft Has Too Much End Play.

10. Clutch Bearings Have Short Service Life.

11. Mechanical Shutoff Fails To Stop Engine Because Of Low Oil Pressure.

12. Mechanical Shutoff Does Not Stop Engine When Coolant Temperature Is Too High.

13. Mechanical Shutoff Will Not Let Engine Start.

14. Electrical Gauges Give Wrong Readings.

15. PSG Governors.

a. Engine Speed Does Not Have Stability.

b. Vibration At Governor Output Shaft.

c. Fuel Control Response When The Engine Is Started Is Not Acceptable.

d. Engine Has Slow Response To A Change In Speed Setting Or Load.

e. No Output From Governor.

f. Engine Will Not Drive Full Rated Load.

g. Load Sharing Between Paralleled Units Is Not Correct (One unit on zero droop all others on droop).

h. Load Sharing Between Paralleled Units Is Not Correct (all units on droop).

16. Automatic Start/Stop Systems.

Contactor Switch For Water Temperature Does Not Activate Shutoff Solenoid

Contactor Switch For Water Temperature Activates Shutoff Solenoid At Wrong Temperature.

Contactor Switch For Oil Pressure Fails To Activate Shutoff Solenoid

Contactor Switch For Overspeed Fails To Activate Shutoff Solenoid.

Contactor Switch For Overspeed Activates Shutoff Solenoid At Wrong Speed.

Shutoff Solenoid Fails To Stop Engine.

Shutoff Solenoid Prevents Engine Start

Clutch Will Not Engage (Slips), Heats Or Lever Moves To Released Position.

Clutch Shaft Has Too Much End Play.

Clutch Bearings Have Short Service Life.

Mechanical Shutoff Fails To Stop Engine Because Of Low Oil Pressure.

Mechanical Shutoff Does Not Stop Engine When Coolant Temperature Is Too High.

Mechanical Shutoff Will Not Let Engine Start.

Electrical Gauges Give Wrong Readings.

Engine Speed Does Not Have Stability.

Vibration At Governor Output Shaft.

Fuel Control Response When The Engine Is Started Is Not Acceptable.

Engine Has Slow Response To A Change In Speed Setting Or Load.

No Output From Governor.

Engine Will Not Drive Full Rated Load.

Load Sharing Between Paralleled Units Is Not Correct (one unit on zero droop all the others on droop).

Load Sharing Between Paralleled Units Is Not Correct (all units on droop).

Automatic Start/Stop System

The charts that follow give some of the problems and probable causes for trouble with automatic start/stop systems.

Measuring Engine Speed

LOCATION FOR TACHOMETER DRIVE ADAPTER
A. Tachometer drive adapter.

Most engines have a location where a tachometer drive adapter can be installed. Install an adapter. Then connect it to the tachometer in the 4S6553 Engine Test Group, the 5P2150 Engine Horsepower Meter or the 1P5500 Portable Phototach Group.

NOTE: On some engines the service meter must be removed.

4S6553 ENGINE TEST GROUP
1. 4S6992 Differential Pressure Gauges. 2. Zero adjustment screw. 3. Lid. 4. 8M2743 Gauge. 5. Pressure tap fitting. 6. 4S6991 Tachometer. 7. 4S6997 Manifold Pressure Gauge.

Special Instruction Form SEHS7341 is with the 4S6553 Engine Test Group. It has instructions on how to use the group.

The 1P5500 Portable Phototach Group can measure engine speed from the tachometer drive on the engine. It can also measure the speed of the engine parts (fan, flywheel, etc.) that have rotation. For the best accuracy the rpm of the part that is measured must be the same as the rpm of the engine. Special Instruction Form SMHS7015 has instructions on how to use the group.

1P5500 PORTABLE PHOTOTACH GROUP

5P2150 ENGINE HORSEPOWER METER

The 5P2150 Engine Horsepower Meter can measure engine speed from the tachometer drive on the engine. It can also measure engine speed from the signal made by a magnetic pickup when the teeth of the flywheel go by it. Special Instruction Form SMHS7050 has instructions for its use. The necessary information to use a magnetic pickup with the 5P2150 Engine Horsepower Meter is given in the following procedures.

Engines With Woodward PSG Governor

Engines which have the Woodward PSG Governor need a different method for measuring engine speed. This is because the adapter for the Woodward PSG Governor takes the place of the tachometer drive shaft. There are several methods for measuring engine speed. Use the one which is best for the work being done.

Tachometer in the Control Panel

If equipped, use the tachometer on the control panel.

Frequency Meter

If the engine is the drive for a generator with a frequency meter use it to measure the engine speed. The frequency meter reading is 60 Hertz at 1800 engine rpm. The frequency meter reading is 50 Hertz at 1500 engine rpm.

1P5500 Portable Phototach Group

1P5500 PORTABLE PHOTOTACH GROUP INSTALLED

The 1P5500 Portable Phototach Group can measure the speed of a rotating part of the engine if it is visible. For more accurate readings, use a part which rotates at the same speed as the engine. Special Instruction Form SMHS7015 has instructions for its use.

Magnetic Pickup

The flywheel housings used on these engines all have an opening for timing the engine. The adapter and magnetic pickup for testing can be installed at this location on all engines for test purposes. In addition, most of the flywheel housings also have a location for installation of the magnetic pickup for use with the electronic speed switch. If there is a magnetic pickup already installed and being used with the electronic speed switch, its signal can be used with an electronic counter or with the 5P2150 Engine Horsepower Meter. The operation of the magnetic pickup is the same for any of the installations.

The signal from the magnetic pickup is an AC voltage. Every tooth on the flywheel makes the signal have one cycle. Each revolution of the flywheel gives the signal one cycle per tooth. When the engine is running the number of teeth on the flywheel multiplied by the number of revolutions per minute gives the number of cycles per minute in the signal. Divide this number by 60 seconds per minute to get the number of Hertz (cycles per second).

The voltage output of the magnetic pickup is normally between 10 to 20 volts AC. If necessary, the voltage can be increased by turning the magnetic pickup in so that it is closer to the flywheel gear. The maximum voltage is approximately 80 Volts AC. These voltages are at normal engine speeds (approximately 1500 rpm).

Show/hide table

NOTICE
Be careful when adjusting the magnetic pickup. Not enough clearance can cause damage to the magnetic pickup.

The voltage also changes with engine speed. Higher speed makes a signal with higher voltage.

Installation Procedure for Magnetic Pickup

The magnetic pickup (2) is to be installed so that the clearance dimension is .022 to .030 in. (0.56 to 0.76 mm) away from the flywheel gear teeth (5).

With the engine stopped, turn the magnetic pickup (2) in until it just has contact with a tooth. Then turn it out 1/2 of a turn. Tighten the locknut (4). This gives approximately the correct clearance dimension.

INSTALLATION OF MAGNETIC PICKUP
1. Clearance dimension. 2. Magnetic pickup. 3. Wires. 4. Locknut. 5. Flywheel gear teeth. 6. Adapter.

Checking the Magnetic Pickup

There are two ways to check a magnetic pickup (2).

One way is to measure the resistance through the magnetic pickup (2) with an accurate ohmmeter. The correct resistance is in the specifications.

The other way is to measure the voltage output with the engine running. This measurement is made with a voltmeter between the wires (3) when the engine is at normal operation speed. The wires (3) must be disconnected from any other circuit during the test. The voltage output must be according to the specifications. If the voltage is not correct and the installation is correct, make a replacement of the magnetic pickup (2).

ADAPTER

A cover for the timing pointer (3B817) which has been drilled and tapped as shown makes an adapter (6) which can fit all of these engines. A magnetic pickup (2) with a 1.5 megohm resistor in series with one of its wires and a phono plug on the end makes a magnetic pickup for testing. Together with the adapter, they make installation quick and easy.

MAGNETIC PICKUP FOR TESTING
2. Magnetic pickup. 4. Locknut. 7. 1.5 megohm resistor (5% or 10%) soldered in series with one wire. 8. Phono plug.

ADAPTER AND MAGNETIC PICKUP FOR TESTING INSTALLED

Electronic Counter

The electronic counter must be able to operate in the range of the signal from the magnetic pickup. The frequency range is 1100 to 6500 Hertz (cycles per second). The voltage range of the magnetic pickup is approximately 4 to 80 volts. If the engine has an electronic speed switch, keep the voltage input to it at 10 to 20 volts AC.

The input resistance of the electronic counter must be more than 1000 ohms if it is used in a parallel circuit with the electronic speed switch. Measure the resistance with an accurate ohmmeter. It is permissible to install resistors in series with the electronic counter to get the correct minimum resistance. This is necessary to keep the signal strong enough for the electronic speed switch to operate correctly.

If the frequency range is not correct, it is permissible to install an electronic frequency multiplier or divider to get the signal in the correct range. If the engine has an electronic speed switch, make sure that the installation does not change the signal which goes to the electronic speed switch. Also be sure that the input resistance of the electronic counter has more than 1000 ohms of resistance.

If the voltage range is not correct, it is permissible to change the adjustment of the magnetic pickup and to add more resistors to the circuit to get the correct voltage. Be sure to keep the voltage of the signal which goes to the electronic speed switch correct.

NOTE: Do not adjust the clearance of the magnetic pickup with the engine running. The end of the magnetic pickup can be damaged by contact with the turning flywheel gear.

When the items are correct according to the description given above, connect the electronic counter to the circuit. Start the engine. The number which is on the electronic counter is in relation to the engine speed. The relation between the engine speed and number on the electronic counter is the result of engine speed, the number of flywheel gear teeth, the factor for the counter and the use of an electronic divider or multiplier on the signal. The factor for the counter can be found easily. Connect the counter to a source of a known frequency. This can be to normal (commercial) or generator set power or to a frequency generator. Look at the number on the electronic counter. This number is in relation to the frequency of the power source by some factor. Use this factor with the information already given to get another factor which is the relation between the number on the electronic counter and the engine speed.

NOTE: When connecting the electronic counter to the source of a known frequency, be sure to keep the input voltage to the electronic counter in the range of the electronic counter.

5P2150 Engine Horsepower Meter

5P2150 ENGINE HORSEPOWER METER

The 5P2150 Engine Horsepower Meter has an electronic counter. It can count the number of Hertz (cycles per second) in the signal from the magnetic pickup. It is necessary to install a resistor in series with one of the wires from the magnetic pickup to keep from damaging the parts in the 5P2150 Engine Horsepower Meter. The magnetic pickup for testing has the correct resistance.

MAGNETIC PICKUP FOR TESTING
1. Magnetic pickup. 2. 1.5 megohm resistor (5 or 10%) soldered in series with one of the wires. 3. Phono plug.

On engines with an electronic speed switch, the signal from its magnetic pickup is strong enough to operate the electronic speed switch and the electronic counter at the same time. Connect the input wires from the 5P2150 Engine Horsepower Meter to the "SIG" and "COM" terminals on the electronic speed switch. Install a 1.5 megohm resistor in series with one of the input wires. This decreases the input voltage to keep from damaging the parts in the 5P2150 Engine Horsepower Meter. The minimum voltage input to the electronic counter is 1.5 volts. If the voltage is too low make an adjustment to the magnetic pickup to get the minimum voltage. Do not make a change to the circuit that causes the voltage at the terminal strip to be less than 10 volts at 1500 engine rpm.

The 5P2150 Engine Horsepower Meter automatically shows the correct engine rpm when it is used with the standard tachometer generator. When it is used with the magnetic pickup, it does not show engine speed directly. This is because the signal from the magnetic pickup has more cycles per revolution of the engine than the standard tachometer generator. The signal from the standard tachometer generator has 10 cycles for each revolution of the engine. The signal from the magnetic pickup has one cycle for each flywheel gear tooth for each revolution of the engine. For example, if the flywheel gear has 156 teeth, there are 156 cycles for each revolution. The number which the meter shows is larger by a factor of 156 ÷ 10 or 15.6. This factor is the factor for the flywheel gear. At lower engine speeds, the number on the meter divided by the factor for the flywheel gear gives the engine speed. At higher engine speeds, the number is too big for the meter. The meter shows the four digits nearest to the decimal point. In the example, 15987, the first digit is 1. The number that the meter shows is 5987.

Look at the chart for the approximate engine rpm. The chart has the correct meter reading for that engine rpm according to the number of flywheel gear teeth. If the number has more than four digits, put the fifth digit from the chart with the number which is shown on the meter. Divide this number by the factor for the flywheel gear. The result is the correct engine rpm. Remember that a change of 1 rpm in engine speed makes a change of 13.2 or 15.6 in the rpm shown on the meter.

Fuel System - (Engines With Woodward PSG Governor)

Refer to the TESTING AND ADJUSTING section of the 3304 and 3306 Industrial and Marine Engine Form No. SENR7053 for all procedures not covered in this section.

Fuel System Setting

5P4203 Field Service Tool Group or3P1550 Field Service Tool Group.

Special Instruction Form No. SMHS7013 is with this group and has instructions for its use.

The following procedure for fuel system setting can be done with the housing for the fuel injection pumps either on or off the engine.

FUEL SYSTEM SETTING
1. Governor control linkage. 2. Lever. 3. Cover.

1. Disconnect the governor control linkage (1) from lever (2).

2. Remove the shutoff solenoid and the fuel ratio control.

3. Remove cover (3).

4. Put the 5P299 Pin (4) into hole (5) as shown.

INSTALLATION OF PIN
4. 5P299 Pin. 5. Hole.

5. Put cover (6) and 3J6956 Spring over pin (4). Use a 1D4533 Bolt and a 1D4538 Bolt to hold cover (6) to the housing for the fuel injection pumps.

NOTE: The 5P6602 Adapter (A) is a replacement for the 5P4226 Adapter and the 2P8331 Cover (6). Either adapter or the cover can be used for this procedure.

6. Put a 8S7271 screw in the hole over the 5P299 Pin (4) and 3J6956 Spring. Tighten the 8S7271 screw until it holds 5P299 Pin (4) against the housing for the fuel injection pumps.

TOOLS INSTALLED
6. Cover. 7. Dial indicator. 8. Clamp.

7. Put clamp (8) in 2P8331 Cover (6) or 5P6602 Adapter (A). Put 3P1569 Magnetic Point or 5P4809 Point on indicator (7) and install indicator (7) in clamp (8).

NOTE: If the indicator automatically goes to the extended position, use the 5P4809 Point. If the indicator does not automatically go to the extended position, use the 3P1569 Magnetic Point.

DIAL INDICATOR IN CONTACT WITH FUEL CONTROL SHAFT
7. Dial indicator. 8. Clamp. 9. 3P1569 Magnetic point. 10. Fuel control shaft.

FUEL SYSTEM SETTING (Typical Example)
11. Contact. 12. 8S4627 Circuit Continuity Tester Light. 13. Clip. A. 5P6602 Adapter.

8. Turn lever (2) in a clockwise direction. This puts the fuel control shaft (10) against the 5P299 Pin (4).

9. Hold lever (2) in that position and adjust both dials on the dial indicator (7) to zero.

10. Connect the clip end (13) of continuity light (12) to a good electrical ground. Put the other end of continuity light (12) in contact with the contact (11) as shown.

11. Turn the 8S7271 Screw counterclockwise. Turn it slowly until the continuity light just goes on.

12. Make a record of the reading on the dial indicator (7).

13. Do this procedure several times to make sure that the reading is correct.

14. Make a comparison of this reading and the FUEL SYSTEM SETTING on the Engine Information Plate or from RACK SETTING INFORMATION. If the reading is not the same, make sure the governor control shaft is in the full load position. Then do Steps 7 through 14 again.

15. If the reading on the dial indicator (7) is not correct, remove the cover from the load stop adjusting screw (14).

16. Loosen locknut (15). Turn it away from the housing for the fuel injection pumps until the star washer (16) can turn without being held by pin (17).

17. Hold star washer (16) above the pin (17), turn the load stop adjusting screw (14), as necessary, to get the correct reading on dial indicator (7). Remember to push lever (2) in the clockwise direction when reading the dial indicator (7).

LOAD STOP ADJUSTING SCREW
14. Load stop adjusting screw. 15. Locknut. 16. Star washer.

STAR WASHER
14. Load stop adjusting screw. 16. Star washer. 17. Pin.

NOTE: If the pin (17) is not in alignment with one of the notches in the star washer (16), turn the speed adjusting screw (14) to put the nearest notch in alignment with pin (17).

18. Tighten the locknut (15). Check the adjustment by going through Steps 7 through 13 again.

19. When the adjustment is correct, install the cover for the load stop adjusting screw (14).

20. Install the fuel ratio control.

NOTE: The arrangement of the tooling for checking the fuel ratio control is the same as for checking the fuel setting. Make reference to Fuel Ratio Control Setting at this time if a check of the fuel ratio control setting is desired.

21. Remove the tooling and install the cover (3) and the shutoff solenoid.

22. Connect the governor control linkage (1) to lever (2) according to the procedure in WOODWARD PSG GOVERNOR.

Fuel Ratio Control Setting

NOTE: The following procedure can be done with the fuel system either on or off the engine. In either way, damage to the fuel system can be the result if dirt gets into the fuel system.

The adjustment of the Fuel Setting must be correct before making checks or adjustments to the Fuel Ratio Control.

Make reference to FUEL SYSTEM SETTING for the correct procedure for checking and making adjustments to the Fuel System Setting.

1. With the tooling still installed from the procedure Fuel System Setting, turn the 8S7271 Screw in until the 5P299 Pin is against the fuel injection housing.

2. Make an adjustment if necessary to make the reading of both dials on the dial indicator be zero.

3. Turn 8S7271 Screw out 6 or more turns. Move the governor control shaft clockwise to the full load position. The reading on the dial indicator must be the same as the Fuel Ratio Control Setting on the ENGINE INFORMATION plates or in RACK SETTING INFORMATION.

NOTE: The reading on the dial indicator has a tolerance of ± .004 in. (± 0.10 mm). This tolerance is for the turning of bolt (1) for the alignment of the bolt holes in the cover (2).

4. If the reading is not correct, remove the cover (2). Turn the bolt (1) with the cover (2) until the reading on the dial indicator is correct. Be sure that the governor control shaft is turned to the full fuel position.

5. Install cover (2).

NOTE: If the bolt holes in the cover (2) are not in alignment with bolt holes in the body (3), turn the bolt (1) with the cover (2) to put the bolt holes in the cover in alignment with the nearest holes on the body (3).

FUEL RATIO CONTROL
1. Bolt. 2. Cover. 3. Body.

Woodward PSG Governor

NOTE: Make sure that the adjustment of the governor control linkage is correct before making any other adjustments.

Adjusting Governor Control Linkage

GOVERNOR CONTROL LINKAGE
1. Lever. 2. Lever. 3. Governor control linkage.

1. Turn lever (2) to its farthest counterclockwise position.

2. Turn lever (1) on the Woodward PSG Governor to its farthest counterclockwise position.

3. Adjust the governor control linkage (3), if necessary, to put the bolt hole in the end of the governor control linkage (3) in alignment with the bolt hole in lever (2).

Adjusting The Needle Valve

WOODWARD PSG GOVERNOR
1. Needle valve. 2. Knurled knob. 3. Synchronizing motor.

NOTE: The Woodward PSG Governor is removed from the engine to show the needle valve (1). When the governor is installed on the engine, the needle valve (1) is between the governor and the cylinder block.

1. Start the engine and let it run at normal operating conditions. Adjust the engine speed with the knurled knob (2) if necessary to get the engine running at the normal engine speed.

2. Turn compensating needle valve (1) two or three turns counterclockwise. Let the engine hunt for about 30 seconds. This lets air out of the hydraulic circuit in the governor.

3. Turn the needle valve slowly clockwise until the engine speed has stability. Put a near full load on the engine. Again turn the needle valve slowly clockwise until the engine speed has stability.

NOTE: 1/4 turn out from the seat is the approximate point of best stability.

4. Check the action of the governor by moving lever (4) to the shutoff position as shown. When the engine speed starts to decrease, release lever (4). If the governor is operating correctly, there should be a rapid return to the normal engine speed with only a small amount of overshoot (engine runs faster than normal).

WOODWARD PSG GOVERNOR INSTALLED
2. Knurled knob. 3. Synchronizing motor. 4. Lever.

5. If the engine hunts more than a small amount before it has stability turn the needle valve clockwise. If the engine is slow to return to the desired speed turn the needle valve counterclockwise. Do steps 4 and 5 until the engine returns to the desired speed and has stability in the shortest amount of time.

Adjusting The High Idle Stop

1. Start the engine and let it run until the coolant temperature is normal.

2. Loosen locknut (3). Turn stop screw (2) counterclockwise approximately two turns.

Show/hide table

NOTICE
With the stop screw in this position the engine can overspeed. This can cause damage to engine components. Be ready to shutdown the engine if it has an overspeed condition.

WOODWARD PSG GOVERNOR INSTALLED
1. Synchronizing motor. 2. Stop screw. 3. Locknut. 4. Knurled knob.

3. Use knurled knob (4) or synchronizing motor (1) to adjust the engine to the desired speed.

NOTE: Early models use a manual adjustment screw.

4. Turn stop screw (2) clockwise until it stops. Tighten locknut (3).

5. If the engine speed is still correct, the adjustment is correct.

Check Speed Droop

The speed droop can be adjusted between zero and seven percent. The desired speed droop will be different for different applications. Percent of speed droop is the percent difference between the engine speed at no load and full load. To calculate speed droop use the formula:

1. Get the desired speed droop for the application.

2. Multiply the full load speed by the desired speed droop. Add the number from this multiplication to the full load speed to get the no load speed.

3. Start the engine and let it run until the temperature of the coolant is normal.

4. Adjust the engine speed to get the no load speed from Step 2.

5. Connect a known load to the engine. The load must be less than the full capacity of the engine. Make a record of the decrease in engine speed.

6. Make a ratio between the load on the engine and the full load capacity of the engine. This ratio must be the same as the ratio between the decrease in engine speed from Step 5 and the number from the multiplication in Step 2. For example:

7. If the ratios are not the same an adjustment of the speed droop is necessary. Remove the load and stop the engine. If the engine speed decreased too much according to the ratio decrease the amount of speed droop. If the decrease in engine speed is not enough increase the amount of speed droop. See SPEED DROOP ADJUSTMENT.

Speed Droop Adjustment (Later PSG Governors)

1. Make a mark on cover (1) to show the original position of bracket (3). This will show how much a change in bracket position changes the speed droop.

2. Loosen knob (2) that holds bracket (3) and speed droop lever (4) in position.

3. To increase the speed droop turn lever (4) counterclockwise. To decrease the speed droop turn lever (4) clockwise.

NOTE: If the lever is turned clockwise beyond the point where the speed droop is zero the engine will hunt a large amount and will not get stability.

4. Tighten knob (2) to hold the lever and bracket in position. After an adjustment is made check the speed droop. See CHECK SPEED DROOP. Several adjustments can be necessary to get the desired speed droop.

5. When lever (4) is in the position that gives the desired speed droop, set stop screw (5) against the pin on lever (4). This will make it easy to return the speed droop lever to the desired position after disassembly and assembly of the governor.

PSG GOVERNOR (Later)
1. Cover. 2. Knob. 3. Bracket. 4. Speed droop lever. 5. Stop screw.

Speed Droop Adjustment (Earlier PSG Governors)

9S215 Dial Indicator5P7285 Adjusting Bracket3P1565 Collet

1. Remove cover (1) from the governor.

Show/hide table

Cover (1) is pushed away from the body of the governor by a strong spring (5). Loosen all the bolts that hold the cover in position evenly to decrease the force of compression in spring (5).

2. Make a mark on output shaft lever (4) to show the original position of bracket (3). This will show how much a change in bracket position changes the speed droop.

3. Loosen screw (7) that holds bracket (3) in position.

PSG GOVERNOR (EARLIER)
1. Cover. 2. Lever. 3. Bracket. 4. Output shaft lever. 5. Spring. 6. Pilot valve.

4. To increase the speed droop move bracket (3) in the direction shown by the arrow. To decrease the speed droop move the bracket in the opposite direction.

NOTE: If the bracket is moved in the direction opposite the arrow beyond the point where the speed droop is zero the engine will hunt a large amount and will not get stability.

SPEED DROOP ADJUSTMENT
3. Bracket. 7. Screw. 8. Output shaft.

NOTE: Zero droop position can be set by the use of a 5P7285 Adjusting Bracket (10), 3P1565 Collet (11) and 9S215 Dial Indicator (9). Install the bracket and collet on the governor. Install the indicator in the collet. Put the tip of the indicator on lever (2) above pilot valve (6). Turn output shaft (8) and look at the indicator. Adjust bracket (3) until rotation of the output shaft causes no movement of the indicator.

TOOLS INSTALLED
9. 9S215 Dial indicator. 10. 5P7285 Adjusting Bracket. 11. 3P1565 Collet.

Pilot Valve Adjustment

WOODWARD PSG GOVERNOR INSTALLED
1. Pipe plug opening.

Check the adjustment of the pilot valve when the governor is disassembled (linkage and top cover removed).

Show/hide table

The top cover is pushed away from the body of the governor by a strong spring. Loosen all the bolts that hold the cover in position evenly to decrease the force of compression of the spring.

1. Remove the pipe plug from inspection opening (1).

2. Use a light to look for the control opening in pilot valve bushing (2) and regulating land (3) on the pilot valve.

CONTROL OPENING
1. Inspection opening. 2. Pilot valve bushing. 3. Regulating land. A. Port opening. B. Port opening.

3. Push pilot valve (6) in the direction of the drive end as far as possible. Check the length of port opening (A).

4. Pull the pilot valve in the opposite direction as far as possible. Check the length of port opening (B).

PSG GOVERNOR
2. Pilot valve bushing. 3. Regulating land. 4. Locknut. 5. Spring seat. 6. Pilot valve.

5. The length of port opening (A) must be the same, within .010 in. (0.25 mm), as port opening (B).

6. If the lengths of the port openings are not correct hold spring seat (5) with 1P87 Adjusting Wrench. Loosen locknut (4). Turn the pilot valve as necessary to get the correct adjustment.

NOTE: Turn the pilot valve clockwise to increase port opening (A) and decrease port opening (B). Turn it counterclockwise to decrease port opening (A) and increase port opening (B).

1P87 ADJUSTING WRENCH USED TO HOLD SPRING SEAT

7. Tighten locknut (4) and remove the wrench.

8. Check the adjustment according to Steps 3, 4 and 5.

Show/hide table

NOTICE
If this adjustment is not correct the engine can have an overspeed condition. This can cause damage to engine components.

9. When the adjustment is correct, put 8H5137 Gasket Sealant on the threads of the pipe plug and install it in pipe plug opening.

Procedure To Remove Adapter For Woodward PSG Governor

1. Remove bolt (5) holding rod (3) to lever (4). Remove the oil line (7). Disconnect the control wire (6) to the synchronizing motor (1). Remove 4 nuts (2) holding Woodward PSG Governor (8) to the cover assembly (9). Remove governor.

2. Remove the bolts holding cover assembly (9) to housing assembly (10). Remove the cover assembly (9).

WOODWARD PSG GOVERNOR INSTALLED
1. Synchronizing motor. 2. Nut. 3. Rod. 4. Lever. 5. Bolt. 6. Control wire. 7. Oil line. 8. Woodward PSG Governor. 9. Cover assembly. 10. Housing assembly.

SUPPORT ASSEMBLY INSTALLED
11. Drive sleeve. 12. Support assembly.

3. Remove drive sleeve (11). Remove the support assembly (12).

HOUSING ASSEMBLY
10. Housing assembly. 13. Bolt.

4. Remove bolt (13). Remove housing assembly (10).

5. Remove shaft (14) and adapter (15). Remove shaft (16) and lever assembly (17).

REMOVING SHAFT FROM ADAPTER
14. Shaft. 15. Adapter. 16. Shaft. 17. Lever.

Procedure To Install The Adapter For The Woodward PSG Governor

INSTALLING SHAFT
1. Lever assembly. 2. Shaft. 3. Adapter. 4. Shaft.

1. Install the lever assembly (1) and shaft (2) in the fuel injection pump housing.

2. Install adapter (3) with three bolts. Install shaft (4) in the adapter (3).

3. Loosen the bolt holding lever (5) on shaft with lever (6).

4. With lever (6) against the housing assembly (7) push the pin in lever (5) in the direction shown. Tighten the bolt holding lever (5). This lets the linkage from the governor move the linkage in the fuel injection pump for the maximum amount of fuel.

HOUSING ASSEMBLY
5. Lever. 6. Lever. 7. Housing assembly.

5. Install the housing assembly (7) on the housing for the fuel injection pump with bolt (8).

6. Install the support assembly (9) and drive sleeve (10).

HOUSING ASSEMBLY INSTALLED
7. Housing assembly. 8. Bolt.

SUPPORT ASSEMBLY
9. Support assembly. 10. Drive sleeve.

7. Install the cover assembly (11). If there is a fuel ratio control, make reference to FUEL RATIO CONTROL SETTING.

COVER ASSEMBLY INSTALLED
11. Cover assembly. 12. Shutoff housing.

8. Make sure that the levers in the shutoff housing (12) operate correctly after the cover assembly (11) is installed.

9. Install the Woodward PSG Governor (20) on the cover assembly (11). Install the oil line (19) and connect the rod (15) to lever (16) with bolt (17). Make reference to GOVERNOR LINKAGE ADJUSTMENT. Connect the control wires (18) to the synchronizing motor (13).

WOODWARD PSG GOVERNOR INSTALLED
7. Housing Assembly. 11. Cover Assembly. 13. Synchronizing motor. 14. Nuts. 15. Rod. 16. Lever. 17. Bolt. 18. Control wire. 19. Oil line. 20. Woodward PSG Governor.

Shutoff And Alarm System Components

Contactor Switch For Oil Pressure

3P1564 Pressure Gauge (0 to 60 psi).3B7734 Pipe Nipple, 1/8 in. X 3.5 in.3B6483 Cap.Two 3B7263 Pipe Nipples, 1/8 in. X 2 in.Two 3B9389 Shutoff Cock Fittings.Two 1F9369 Tees.44914 Tee.Two 5K3772 Hose Assemblies.8S4627 Circuit Tester.

TEST EQUIPMENT
1. 3P1564 Pressure gauge (0 to 60 psi). 2. 3B7734 Pipe nipple. 3. 3B6483 Cap. 4. Oil supply line. 5. 3B7263 Pipe nipple. 6. 3B9389 Shutoff cock fitting. 7. 3B9389 Shutoff cock fitting. 8. 1F9369 Tees. 9. 5K3772 Hose Assemblies. 10. 44914 Tee.

Test Procedure

1. Remove the cover of the contactor switch and disconnect the wires from the normally closed (B or Blue) terminal.

2. Disconnect the oil supply line from the contactor switch and install the test equipment as shown.

3. Connect the 5K3772 Hose from tee (10) to the contactor switch. Put the end of the other 5K3772 Hose in a pan.

4. Connect the 8S4627 Circuit Tester between the common terminal and the normally closed terminal. The light of the circuit tester will be activated.

5. Close shutoff fitting (7) and open shutoff fitting (6).

6. Look at the pressure gauge, start the engine and run it at low idle rpm. The light must go out, with an increase in oil pressure, at the specification of the switch.

7. Close shutoff fitting (6) and slowly open shutoff fitting (7). The light must be activated, with a decrease in oil pressure, at the specification of the switch.

8. Stop the engine.

9. Connect the wire(s) to the normally closed terminal.

10. On contactor switches with a button or a control knob either push the button or turn the knob to the OFF position.

11. Close shutoff fitting (7) and open shutoff fitting (6).

12. Start the engine and run it at low idle rpm.

13. Put a jumper wire between the common terminal and the normally closed terminal. This will check the system beyond the contactor switch.

14. Remove the jumper wire.

Adjustment of Earlier Type Switch

CONTACTOR SWITCH FOR OIL PRESSURE (Earlier Type)
11. Adjustment screw. 12. Main spring.

1. Turn adjustment screw (11) counterclockwise to make a decrease in the tension of main spring (12).

2. Disconnect the wires from the normally closed terminal of the switch.

3. Start the engine and run it at low idle rpm.

4. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the pressure gauge shows the pressure specification at which the switch must close with a decrease in pressure. Close shutoff fitting (7).

5. Make sure the control knob is in RUN position, if so equipped.

6. Connect the 8S4627 Circuit Tester between the common terminal and the noramlly closed terminal. The light of the circuit tester must not be activated.

WIRING CONNECTIONS
A. Normally open terminal. B. Common terminal. C. Normally closed terminal.

7. Turn screw (11) clockwise until the light of the circuit tester is activated.

8. To check the adjustment, close shutoff fitting (7) and open shutoff fitting (6).

9. Connect the wires to the normally closed terminal.

10. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the engine stops or the alarm operates.

11. The pressure gauge must show the correct pressure specification of the switch as the engine stops or the alarm operates.

Adjustment of Micro Switch Type

1. Loosen locknut (16) and turn adjustment screw (14) counterclockwise to make a decrease in the tension of spring (15).

CONTACTOR SWITCH FOR OIL PRESSURE (Micro Switch Type)
13. Set for start button. 14. Adjustment screw. 15. Spring. 16. Locknut. 17. Contact button.

2. Disconnect the wires from the normally closed terminal of the switch.

3. Start the engine and run it at low idle rpm.

4. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the pressure gauge shows the pressure specification at which the switch must close with a decrease in pressure. Close shutoff fitting (7).

5. Make sure the set for start button (13) is in the RUN position.

6. Connect the 8S4627 Circuit Tester between the common terminal and the normally closed terminal. The light of the circuit tester must not be activated.

7. Turn screw (14) clockwise until the light of the circuit tester is activated.

8. Tighten the locknut.

WIRING CONNECTIONS
D. Normally closed B terminal. E. Normally open W terminal. F. Common R terminal.

9. To check the adjustment, close shutoff fitting (7) and open shutoff fitting (6).

10. Connect the wires to the normally closed terminal.

11. Close shutoff fitting (6) and slowly open shutoff fitting (7) until the engine stops or the alarm operates.

12. The pressure gauge must show the correct pressure specification of the switch as the engine stops or the alarm operates.

Contactor Switch For Water Temperature

Fabricated heat sink.2F7112 Thermometer.3J5389 Plug.8S4627 Circuit Tester.

Method of Checking

1. Make a heat sink as shown. Material can be brass, steel or cast iron. Drill a 23/32 in. hole through the plate and use a tap to make 1/2 in. NPT threads.

2. Put marks on the two contactor wires that connect the contactor to the circuit. Disconnect the two wires.

HEAT SINK [Dimensions in inches (mm)].

3. Remove the contactor and install a 3J5389 Plug. Install the contactor switch in the heat sink.

4. Put the heat sink and contactor in water as shown. Use blocks to support the heat sink at surface level.

5. Connect the 8S4627 Circuit Tester between the wires that connected the contactor to the circuit.

TEST OF CONTACTOR SWITCH
1. 2F7112 Thermometer. 2. Fabricated heat sink.

6. Put the 2F7112 Thermometer in the water.

7. Use a torch to heat the water to the temperature range at which the contactor must activate. If the circuit tester light does not come on within the temperature range given in the specifications make a replacement of the contactor.

8. Let the water temperature go down. If the circuit tester light does not go out within the temperature range given in the specifications make a replacement of the contactor.

Pressure Switch With Time Delay

8M2743 Gauge.8S4627 Circuit Tester.

1. Remove the pressure switch (2) from the tee.

OIL PRESSURE SWITCH WITH TIME DELAY INSTALLED
1. Damper. 2. Pressure switch. 3. Valve.

2. Install a short nipple, shutoff valve and short nipple and another tee in the place of the pressure switch (2). Make sure that the valve is closed.

3. Install the pressure switch (2) and a 8M2743 Gauge in the open ends of the tee.

4. Connect the 8S4627 Circuit Tester between the terminals of the pressure switch.

TEST TOOLING INSTALLED

5. Start the engine. Open the shutoff valve a small amount. Look at the pressure on the 8M2743 Gauge. When the pressure gets to the range given in the specifications the circuit tester light must go on.

6. Close the shutoff valve. Stop the engine. Open the shutoff valve a small amount. Look at the pressure on the 8M2743 Gauge. When the pressure gets to the range given in the specifications close the valve. After five minutes open the valve fully. The circuit tester light must stay on a minimum of 30 seconds and a maximum of 15 minutes after the valve is fully opened.

Shutoff Solenoid

Two checks must be made on the engine to give proof that the solenoid adjustment is correct.

1. The adjustment must give the piston enough travel to move the sleeve control shaft to the shutoff position.

2. The adjustment must give the piston enough travel to cause only the "hold in" windings of the solenoid to be activated when the sleeve control shaft is held in the fuel closed position. Use a thirty ampere ammeter to make sure the plunger is in the "hold in" position. Current needed must be less than one ampere.

ACTIVATE TO RUN
1. Shutoff Solenoid. 2. 9L6588 Spring. 3. 3N2835 Shaft.

ACTIVATE TO SHUTOFF
1. Shutoff solenoid. 4. Distance from face of piston to inside face of shaft (5). 5. 3N2836 Shaft.

Oil Pressure And Water Temperature Shutoff (Mechanical)

9S9102 Thermistor Thermometer Group,2F7112 or a 7F6785 Thermometer.

MECHANICAL SHUTOFF GROUP
1. Tee. 2. Oil line. 3. Shutoff housing. 4. Oil line. 5. Control valve. 6. To timing gear cover.

1. Make a restriction to the flow of air through the radiator or to the flow of coolant through the engine.

2. Install a probe or a thermometer as close as possible to the control valve.

3. Run the engine. The engine must stop in less than one minute from the time that the temperature of the coolant gets to the opening temperature for the control valve.

4. If the engine stops at the correct temperature, both the control valve and the oil pressure shutoff are operating correctly. If the engine does not stop at the correct temperature, do the following steps:

5. Loosen one of the connections on the oil supply line for the oil pressure shutoff. If the engine stops running, make a replacement of the control valve. If the engine does not stop running from loosening the nut, stop the engine.

CONTROL VALVE FOR MECHANICAL SHUTOFF

6. Check the lines and fittings and the parts in the shutoff housing for a problem. Make reference to the Systems Operation for information on how the parts work together.

7. Make replacements as necessary and go through Steps 1 through 4 again.

Contactor Switch For Overspeed

The original setting of the contactor switch for overspeed will stop the engine when the engine rpm is more than 18% above full load rpm. DO NOT check the adjustment of the contactor switch on the engine.

Off Engine Adjustment

4S6553 Engine Test Group.8S4627 Circuit Tester.5L2277 Adapter.Reversible Variable Speed Drill.

1. Connect the 1P7443 or 4S6991 Tachometer of the 4S6553 Group to the tachometer generator (2).

2. Connect the 5L2277 Adapter (3) to the contactor switch and tachometer generator (2).

3. Install variable speed drill (4) to the adapter as shown.

4. Connect the 8S4627 Circuit tester (5) between the NO and the C terminals of the contactor switch. The light must be off. If the light is on, push reset button (6).

CHECKING CONTACTOR SWITCH FOR OVERSPEED
1. 4S6553 Engine Test Group. 2. Tachometer generator. 3. 5L2277 Adapter. 4. Variable speed drill. 5. 8S4627 Circuit Tester.

5. Gradually make an increase in the rpm. Read the rpm on the tachometer at the moment the light of the circuit tester is activated. The reading will give the engine rpm (2 rpm on the scale for each rpm the input shaft is turned).

6. If needed, make an adjustment to the contactor switch by loosening lock screws (7). Turn the cap clockwise to lower the overspeed setting. Tighten the lock screws.

7. To check other components in the system, put a jumper wire between the "C" and "NO" terminals of the contactor switch.

OVERSPEED CONTACTOR SWITCH
6. Reset button. 7. Lock screws.

Electronic Speed Switch (Earlier)

NOTE: Some of the early 3N7478 Overspeed Contactor Groups have a speed switch that activates and stops the engine at 25% of the overspeed set point. A method of identification for these early 25% speed switches is to look at terminals 7 and 9. The electrical code letters for these terminals are wrong. Terminal 7 has the letters (NC) and terminal 9 has the letters (NO). Make a change to these two terminals so the letters for terminal 7 are (NO) and the letters for terminal 9 are (NC). After the change is made, put a mark on the speed switch to show the change to the terminals and also make a mark so it is known that it is a 25% speed switch. The speed switch in the 3N9595 Overspeed Contactor Group and in the later 3N7478 Overspeed Contactor Groups activate at 75% of the overspeed set point. The speed switch in each of these groups has an identification mark to show it is a 75% speed switch.

There are two components to check if there is problem with the operation of the electronic speed switch; the magnetic pickup and the switch operation.

Checking the Magnetic Pickup

MAGNETIC PICKUP
1. Clearance. 2. Wires.

1. Check the resistance of the magnetic pickup with the wires (2) disconnected and the engine stopped. The resistance must be according to specifications.

2. Start the engine. Check the voltage output of the magnetic pickup with the engine running at normal speed. The output must be according to specifications.

MAGNETIC PICKUP INSTALLED

NOTE: If the voltage output is not correct according to specifications, check for the correct clearance (1) between the magnetic pickup and the flywheel gear teeth.

3. If the operation of the magnetic pickup is correct according to the specifications after the tests above, connect the wires and check the operation of the electronic speed switch.

Overspeed Adjustment

ELECTRONIC SPEED SWITCH (EARLIER)
1. Cover.

1. Remove cover (1). Make a temporary connection between terminals 1 and 2 of the speed switch.

2. Make reference to ENGINE SPEED MEASUREMENT. Use one of the methods given to measure the engine speed.

3. Start the engine. Make reference to the overspeed adjustment chart. Slowly increase the speed of the engine. The engine must stop at the overspeed setting according to the rated full load speed of the engine. For example, if the rated full load speed is 1800 rpm, the engine should stop at 531 rpm or 1593 rpm.

4. If the speed switch does not stop the engine at the correct overspeed test rpm remove screw (3). Use a small screwdriver to turn the adjustment screw behind screw (3).

NOTE: Turn the adjustment screw clockwise to increase or counterclockwise to decrease the rpm at which the engine will stop.

ADJUSTMENT LOCATIONS
2. Screw. 3. Screw.

Cranking Adjustment

NOTE: Some earlier electronic speed switches do not have a cranking adjustment.

1. If the starter motor pinion does not move away from the flywheel at 600 rpm screw (2). Use a small screwdriver to turn the adjustment screw behind screw (2).

NOTE: Turn the adjustment screw clockwise to increase or counterclockwise to decrease the rpm at which the starter motor pinion moves away from the flywheel.

Electronic Overspeed Switch

Wiring Diagram

SHUTOFF SYSTEM WIRING DIAGRAM
1. Oil pressure switch. 2. Water temperature contactor. 3. Time delay switch. 4. Diode assembly. 5. 75% verify button. 6. Reset button. 7. "LED" overspeed light. 8. Seal screw plug (overspeed). 9. Seal screw plug (crank terminate). 10. Shutoff solenoid. 11. Magnetic pickup. 12. Engine flywheel. 13. Voltage input. 14. Locknut. 15. Air gap.

Troubleshooting Procedure (Overspeed)

Troubleshooting Procedure (Crank Terminate)

NOTE A. DO NOT LEAVE STARTER MOTOR ENGAGED WITH THE ENGINE RUNNING.

To perform test measurements use one of the three methods that follows to disengage the starter motor:

1. Connect speed switch terminal 10 to terminal 11 to disengage the starter motor.

2. Use a toggle switch to control the magnetic switch. Connect toggle switch in series with the magnetic switch coil lead.

3. Connect a starter tester that has a manual disconnect control.

NOTE B. Make reference to the SPEED SPECIFICATION CHART for the correct overspeed or crank terminate speed setting

Procedure A

Overspeed Setting Calibration

ELECTRONIC OVERSPEED SWITCH
5. Verify button. 6. Reset button. 7. "LED" overspeed light. 8. Seal screw plug (overspeed). 9. Seal screw plug (crank terminate).

1. Remove lockwire and seal from seal screws (8 & 9). Remove seal screw (8) from access hole for overspeed adjustment screw.

2. Use a small screwdriver and lightly turn O.S. (overspeed) adjustment potentiometer twenty turns in the direction of "MAX ARROW" (clockwise).

NOTE: The overspeed adjustment screw is made so that it can not cause damage to the potentiometer or be removed if the adjustment screw is turned too much.

3. Run engine at 75% of desired overspeed setting rpm. Make reference to the SPEED SPECIFICATION CAHRT.

4. With engine at 75% of overspeed setting rpm, push VERIFY pushbutton (5) and hold in. Turn O.S. (overspeed) adjustment potentiometer in the direction opposite of "MAX ARROW" (counterclockwise) slowly until "LED" overspeed light (7) comes on. Engine will shut down if speed switch is connected to the fuel shutoff solenoid.

5. To reset speed switch, push in reset button (6). Air inlet shutoffs must be manually reset.

6. Slowly turn O.S. (overspeed) adjustment potentiometer approximately one turn clockwise and do Steps 3, 4 and 5 again.

NOTE: More adjustment may be needed to get the correct setting. Turn adjustment potentiometer clockwise to increase speed setting and counterclockwise to decrease speed setting. Turn adjustment potentiometer very slowly only a small amount at a time until adjustment is correct.

7. When the speed setting is correct, install seal screw (8) for overspeed adjustment hole and install lockwire and seal.

Procedure B

Magnetic Pickup Adjustment

MAGNETIC PICK-UP
12. Engine flywheel. 14. Locknut. 15. Air gap.

1. Stop engine.

2. Loosen magnetic pick-up locknut (14).

3. Turn the magnetic pick-up clockwise until contact is made with the teeth of the engine flywheel ring gear (12).

4. Turn the magnetic pick-up counterclockwise one-half turn. This will give approximately .022 to .033 in. (0.56 to 0.84 mm) clearance at location (15), between the end of the magnetic pick-up and the teeth of the flywheel ring gear.

5. After the clearance is correct, tighten the magnetic pick-up locknut to a torque of 50 ± 10 lb. ft. (70 ± 14 N·m).

NOTE: Be sure the magnetic pick-up does not turn when the locknut is tightened.

Procedure C

Crank Terminate Speed Adjustment

1. Remove lockwire and seal from seal screws (8 & 9). Remove seal screw (9) from access hole for crank terminate adjustment screw.

2. Use a small screwdriver and lightly turn C.T. (crank terminate) adjustment potentiometer twenty turns in the direction of "MAX ARROW" (clockwise).

NOTE: The crank terminate adjustment screw is made so that it can not cause damage to the potentiometer or be removed if the adjustment screw is turned too much.

3. Turn the crank terminate adjustment potentiometer twelve turns in a direction opposite of "MAX ARROW" (counterclockwise) for an approximate crank terminate setting.

4. Start engine and make a note of the speed at which the starter disengages. See the SPEED SPECIFICATION CHART for the correct crank terminate speed.

NOTE: If setting is not correct do Steps 5 and 6. If setting was correct do Step 7.

5. Stop engine and turn adjustment potentiometer (clockwise to increase and counterclockwise to decrease) crank terminate speed.

6. Start and make a note of the speed at which the starter disengages. If needed, make more small adjustments until the crank terminate speed is correct.

7. Install seal screw (9) for crank terminate adjustment hole and install lockwire and seal.

ELECTRONIC OVERSPEED SWITCH
5. Verify button. 6. Reset button. 7. "LED" overspeed light. 8. Seal screw plug (overspeed). 9. Seal screw plug (crank terminate).

Procedure D

Overspeed Verify Test

1. Run engine at rated speed, push verify button (5) in for a moment. This will cause the speed switch to activate and shut down the engine.

NOTE: Any time the engine speed is 75% or more of the overspeed setting, the engine will shut down if the verify button is pushed.

EXAMPLE: For an engine with a rated speed of 1500 rpm the overspeed setting is 1770 rpm. The overspeed verify test will shut down the engine at 75% of the overspeed setting of 1770 rpm. In this example 75% of 1770 rpm is 1328 rpm. If the verify button is pushed at an engine speed of 1328 rpm or above the engine will shut down.

The "LED" overspeed light (7) will come on and stay on until the reset button is pushed after an overspeed switch shut down. To restart the engine, push in reset button (6) for a moment. This will reset the speed switch and the rack shutoff solenoid. The "LED" overspeed light (7) will go off. The air inlet shutoff must be manually reset.

NOTE C: To verify overspeed shutdown system operation, push in for a moment the verify push button. The engine must shut down at 75% or more of overspeed setting.

NOTE D: Input Voltage: Maximum 37 VDC Minimum 8 VDC.

NOTE E: The engine overspeed setting rpm is 118% of rated engine rpm.

NOTE F: The magnetic pick-up frequency (HZ) at the overspeed or cranking termination setting is calculated with the formula that follows:

If the rated speed of the engine is other than shown in the chart, the magnetic pick-up frequency for the overspeed setting can be found according to NOTES E and F.

If a 2301 Governor is used, only one magnetic pick-up is needed. Use the magnetic pick-up from the overspeed group. Connect the wires from the magnetic pick-up to the overspeed switch and then connect wires from the speed switch to the 2301 Governor. The overspeed switch can be installed close to the 2301 Governor if needed.

To reset overspeed switch, push in reset button for a moment.

Power Takeoff Clutches

Clutch Adjustment

The force (pull) needed to engage the clutch gives an indication of clutch adjustment. The correct lever pull is shown in the chart.

These clutches use two types of adjustment lock pins. Pin (1) must be pushed in and the adjustment ring turned. Pin (2) must be pulled out and the adjustment ring turned.

CLUTCH ADJUSTMENT
1. Lock pin (push type). 2. Lock pin (pull type).

Assembly Adjustments

End Play For Shaft Bearings

1. With the bearings installed on the shaft, install the shaft in the housing.

2. Tighten the bearing retainer until there is no end play of the shaft.

3. Turn the bearing retainer out the number of notches shown in the chart.

4. Hit the output end of the shaft with a soft hammer to move the bearing cup against the retainer.

5. Measure the end play for the shaft. The correct end play is shown in the chart.

6. If necessary make an adjustment to the retainer to get the correct end play using the procedure in Steps 2 through 5.

7. Install the lock for the retainer.

Installing Hub Nut

1. Tighten hub nut to 30 lb. ft. (40 N·m).

2. For 2N7078 and 2N6961 Clutches, tighten the hub nut 150° to 180° more.

3. For 1N7309 and 2F8223 Clutches, tighten the hub nut 60° to 90° more.

Checking Flywheel And Flywheel Housing

Before installing the clutch, make a check of the bore and face of the flywheel and flywheel housing.

Make reference to the Testing and Adjusting section for the correct procedures and specifications.

Instruments And Gauges

Oil Pressure Sending Units

SENDING UNIT FOR OIL PRESSURE
1. Terminal. 2. Fitting.

1. Connect the sending unit to a pressure source that can be measured with accuracy.

2. Connect an ohmmeter between fitting (2) and terminal (1).

3. Take resistance readings at the pressure shown in the chart.

4. If a unit does not have the correct resistance readings make a replacement of the unit.

Water Temperature Sending Unit

1. Connect an ohmmeter between terminal (1) and nut (2). Put bulb (3) in a pan of water. Do not let the bulb have contact with the pan.

SENDING UNIT FOR WATER TEMPERATURE
1. Terminal. 2. Nut. 3. Bulb.

2. Put a thermometer in the water to measure the temperature.

3. Take resistance readings at the temperatures shown in the chart.

4. If a unit does not have the correct resistance readings make a replacement of the unit.

Electric Gauges

1. Put the gauge in position with the letters horizontal and the face 30° back from vertical.

WIRING DIAGRAM FOR TEST
1. Terminal (for test voltage). 2. Test resistance.

2. Connect the gauge in series with the power source and the middle test resistance shown in the chart.

3. Let the gauge heat at the middle resistance for 5 minutes, then check the pointer position for all of the resistances given.

Mechanical Gauges For Temperature

Two types of mechanical gauges are available. The first type has a direct reading face. The second type has color codes on the face to show different ranges of operation. White, green and red show the cold, normal and hot ranges respectively.

To check both types of gauges, put the bulb of the gauge in a pan of oil. Do not let the bulb touch the pan. Put a thermometer in the oil to measure the temperature. Make a comparison of temperatures on the thermometer with the temperatures on the direct reading gauge or with temperature as shown on the chart for gauges with color codes.

DIRECT READING GAUGE

GAUGE WITH COLOR CODE

Mechanical Gauges For Oil Pressure

Two types of mechanical gauges are available. The first type has a direct reading face. The second type has color codes on the face to show different ranges of operation. Red, white and green show the low pressure, pressure at low idle rpm and normal pressure ranges respectively. Some of the direct reading gauges are for gear oil pressure.

NOTE: Some gauges with color codes have only two ranges. Red for low pressure and green for normal pressure.

To check both types of gauges connect the gauge to a pressure source that can be measured with accuracy. Make a comparison of pressures on the gauge of test equipment with the pressures on the direct reading gauge or with the pressures as shown on the chart for gauges with color codes.

GAUGE WITH COLOR CODE

GAUGE WITH COLOR CODE

DIRECT READING GAUGE