Electrical System

Contactor Switch For Water Temperature

The contactor switch for water temperature is installed in the front cover for the engine. 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.

CONTACTOR SWITCH FOR WATER TEMPERATURE

The contactor switch is connected to the fuel shut-off 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.

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.

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 single switch.

PRESSURE SWITCH

Electrical Gauges And Sending Units

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

Sending Unit and Gauge for Water Temperature

The position of the pointer is changed by the amount of electrical current that flows through the gauge. The water temperature is felt by bulb (3) of the sending unit. A change in water temperature causes a change of resistance in the sending unit. A change in resistance in the sending unit changes the current flow through the gauge and changes the position of the pointer.

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

Sending Unit and Gauge for Oil Pressure

The position of the pointer is changed by the amount of electrical current that flows through the gauge. The oil pressure is felt by the sending unit for the oil pressure gauge. A change in oil pressure causes a change of resistance in the sending unit. A change in resistance in the sending unit changes the current flow through the gauge and changes the position of the pointer.

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

Engine Protection Panel

The engine protection panel has a magnetic control switch (5) in the panel. Pushing in and holding the reset button (4), while cranking the engine, permits the engine to start. When the oil pressure is above 15 psi (105 kPa), the engine will continue to run after button (4) is released.

ENGINE PROTECTION PANEL
1. Oil pressure gauge. 2. Ammeter. 3. Water temperature gauge. 4. Reset button. 5. Magnetic control switch. 6. Fuse.

CONTACTOR SWITCH FOR WATER TEMPERATURE

OIL PRESSURE SWITCH

The normally open contactor switch for water temperature closes when the temperature of the coolant gets higher than the setting of the switch. The oil pressure switch closes when the pressure of the oil gets lower than the setting of the switch. If either the contactor switch for water temperature or the oil pressure switch is activated, they will trip (activate) the magnetic control switch (5). This will open the circuit between the fuel shutoff solenoid and the battery. With no fuel coming to the engine, the engine will stop. A 14 ampere fuse (6) gives protection to switch (5) if there is too much of a load put on it.

12 VOLT STARTING AND CHARGING SYSTEM WITH ELECTRICAL ENGINE PROTECTION PANEL
1. Off, Start Switch. 2. Control panel magnetic switch. 3. Water temperature sending unit. 4. Oil pressure sending unit. 5. Starter solenoid. 6. Starter motor. 7. Hourmeter. 8. Water temperature gauge. 9. Oil pressure gauge. 10. Battery. 11. Ammeter. 12. Fuel shutoff solenoid. 13. Alternator regulator. 14. Water temperature shutoff switch (normally open). 15. Oil pressure shutoff switch (normally closed). 16. Alternator.

12 VOLT STARTING AND CHARGING SYSTEM WITH ELECTRICAL ENGINE PROTECTION PANEL
1. Off, Start Switch. 2. Control panel magnetic switch. 3. Water temperature sending unit. 4. Oil pressure sending unit. 5. Starter solenoid. 6. Starter motor. 7. Hourmeter. 8. Water temperature gauge. 9. Oil pressure gauge. 10. Battery (12V). 11. Ammeter. 12. Resistor diode. 13. Water temperature shutoff switch (normally open). 14. Oil pressure shutoff switch (normally closed). 15. Fuel shutoff solenoid. 16. Alternator.

STARTING AND CHARGING SYSTEM
1. Off, Start Switch. 2. Ammeter. 3. Fuel shutoff solenoid. 4. Starter solenoid. 5. Alternator regulator. 6. Starter motor. 7. Pressure switch (normally open). 8. Alternator. 9. Battery. 10. Hourmeter.

STARTING AND CHARGING SYSTEM
1. Off, Start Switch. 2. Ammeter. 3. Fuel shutoff solenoid. 4. Starter solenoid. 5. Resistor diode. 6. Starter motor. 7. Pressure switch (normally open). 8. Alternator. 9. Battery. 10. Hourmeter.

HIGH WATER TEMPERATURE AND LOW OIL PRESSURE ALARM SYSTEM
1. Water temperature contactor. 2. Oil pressure switch (normally closed). 3. Battery. 4. Toggle switch. 5. Signal light. 6. Horn.

NOTE: Toggle switch (4) can be in the circuit for a way to turn off horn (6).

TACHOMETER WIRING DIAGRAM (One tachometer)
1. Tachometer. 2. Tachometer sending unit.

Power Take-Off Clutches

POWER TAKE-OFF CLUTCHES (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 drive 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 one or two 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 right. 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.