Governors For 3500 Series Engines

Governor Oil Pump

GOVERNOR OIL SUPPLY
1. Oil passages. 2. Passage for oil supply. 3. Passage for oil drain.

The governor drive adapter has four passages with seals. Passages (2 and 3) on the right side are used when the governor is installed on the right side of the engine. Passage (2) is the oil supply to the governor. Passage (3) is the oil drain port for the governor.

Passages (1) with the seals are used when the governor is installed on the left side of the engine.

OIL PASSAGES IN GOVERNOR HOUSING
4. Passage (oil drain). 5. Groove in governor pump housing for O-ring seal. 6. Passage (oil supply).

Passage (4) is for oil drain and passage (6) is for the oil supply in the 3161 Governors.

No gasket is used between the governor and the drive adapter housing. A seal in groove (5) on the outside of the oil pump housing seals between the governor and the large bore in the adapter housing. Replace the large seal and the four counterbore seals each time the governor is removed and installed.

GOVERNOR OIL PUMP ROTATION

Check the direction of the oil pump rotation before the governor is installed on the engine.

Two arrows are cast into the oil pump housing. One arrow indicates counterclockwise, and the other clockwise. A reference ROTATION V is cast in the bottom of the governor housing.

In the above illustration, the counterclockwise arrow is in alignment with the ROTATION V. This is the correct direction of rotation for the 3161 Governor when it is installed on the right hand side of standard rotation 3500 Series Engines.

PUMP ROTATION DECAL

A decal on the outside of the governor housing indicates the direction of governor rotation. This oil pump is set for counterclockwise direction as shown by the decal.

If the direction of rotation of the governor and oil pump is changed, a new decal must be installed with the decal arrow in the correct direction.

OIL PUMP INSTALLATION
7. Roll pin. 8. Reference hole for roll pin. 9. Plug. 10. Location hole for roll pin to change pump rotation. 11. Strap to hold plug in position when pump housing is removed.

To change the direction of pump rotation do the following steps:

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The pump housing holds plug (9) in position. There is spring force on the plug. To prevent injury, mechanically hold plug (9) in the governor housing when the pump housing is removed.

1. Remove the four bolts that hold the pump in place.

2. Use two screwdrivers to lift the pump housing and O-ring seal from the governor.

3. Pull roll pin (7) from the pump housing flange and install it in location hole (10) in the opposite side of the flange.

4. Turn the pump housing and make an alignment of roll pin (7) and reference hole (8) in the governor base.

5. Put a new seal on the oil pump housing. Put clean engine oil on the seal and install the assembly part way into the bore in the base of the governor.

6. Make sure the external pump drive spline is in correct alignment with the internal coupling spline. If the splines are not in alignment, damage to the governor will be the result when the pump housing bolts are installed and tightened.

7. Use a soft faced hammer and hit the outer pump drive shaft so the pump snaps (moves suddenly) in place.

8. Install the four bolts and tighten them to a torque of 10 N·m (90 lb. in.).

9. Make sure the drive shaft turns freely after the bolts have been tightened.

Governor Preparation

INSTALL COVER ON GOVERNOR
1. Location for bolt. 2. Cover.

Because of the close clearance between the fuel control linkage cover and governor, the upper left hand bolt must be installed at location (1) before cover (2) is put on the terminal shaft and the governor is bolted to the drive adapter housing. The other bolts can be put in place after the governor is in position on the engine.

Put clean engine oil on the lip of the seal and install cover over the governor terminal shaft.

CONTROL LEVERS
3. Lever. 4. Lever.

There are two control levers for the 3161 Governor used on 3500 Series Engines. Lever (3) has a fixed pin and lever (4) has an adjustable pin. The fixed pin lever (3) is used on the 3161 Standard and Generator Set Governors.

The adjustable pin lever (4) is used on 3161 Governors with torque rise. Lever (4) is used to synchronize governor torque rise set point (balance point) position to engine fuel setting position.

The adjustable pin lever (4) can be used on a right hand or left hand mounted governor. To convert the lever from right hand governor use to left hand governor use, remove the lock bolt and lock from the adjustable pin. Remove the adjustable pin from the lever, turn it around and install it into the lever the opposite way. Install the lock and bolt into the adjustable pin and tighten just enough to hold it in place. The lever can now be used on the other end of the terminal shaft for left hand mounted governors.

ALIGNMENT OF CONTROL LEVER
5. Notch in fuel control linkage stop lever.

The lever and pin (fixed or adjustable) connect the governor terminal shaft to the fuel control linkage stop lever. The lever pin moves in notch (5) of the stop lever, this causes the two to move together.

INSTALL LEVER
2. Cover. 3. Lever.

The 3161 Standard and Generator Set Governors with fixed pin levers do not require any special adjustments or setting when installed on the engine.

After fuel control linkage cover (2) is in position, install lever (3) on the governor terminal shaft and tighten the bolt to a torque of 25 ± 7 N·m (18 ± 5 lb. ft.). Control levers will go on only the correct way because of the flat and groove of the terminal shaft and the lever pin. This control lever is for right-hand mounted governors. On control levers for left-hand mounted governors, the pin is reversed.

INSTALL LEVER
4. Lever. 6. Bolt.

For 3161 Governors with torque rise, the adjustable pin control lever is installed on the terminal shaft. Bolt (6) is then tightened to a torque of 25 ± 7 N·m (18 ± 5 lb. ft.).

Before the governor is installed on the engine, tighten the pin lock bolt enough to hold the pin in position when the governor is installed on an engine.

After the governor is installed on an engine, the adjustable pin is turned to synchronize the governor travel to the fuel control linkage. See Governor Installation for the correct adjustment and setting of these governors.

Governor Installation

3161 Standard and Generator Set Governors

INSTALL SEALS
1. O-ring seals. 2. O-ring seals.

1. Make sure the four O-ring seals (1) and (2) are in position on the governor drive housing. Install the seal on the governor oil pump housing and put clean engine oil on all seals.

INSTALL GOVERNOR

2. Put the governor and cover gasket in position. Make sure the governor drive shaft and the spline drive are in correct alignment. Also, make sure the pin on the governor lever is engaged in the slot in the fuel control linkage stop lever.

ALIGNMENT OF GOVERNOR AND DRIVE (Cover removed for photo illustration only)
3. Governor oil pump housing. 4. Governor drive shaft. 5. Internal spline coupling.

NOTE: Be sure there is no binding, side load on the drive shaft, or looseness in the drive coupling. The maximum runout of the governor drive shaft and coupling must be less than 0.15 mm (.006 in.). Parts that do not fit correctly or are not in alignment can cause early wear, shaft seizure, or governor drive shaft failure.

FASTEN GOVERNOR TO DRIVE HOUSING
6. Cover. 7. Bolts.

3. Move the governor to put cover (6) in correct alignment (square) with the front housing of the engine. With the governor in alignment, install and tighten bolts (7) to hold the governor to the drive housing.

INSTALL COVER AND BRACKET
6. Cover. 8. Bracket.

4. Put cover (6) against the front drive housing and make sure the gasket is in alignment. Install and tighten the bolts. Check the governor terminal shaft for free movement, see Step 6.

5. Install bracket (8) as follows:

a. Install two bolts in the side of the governor.

b. Slide bracket (8) in place on the bolts. Tighten the bolts enough to hold bracket (8) in position. The bracket must be free enough to move.

c. Install and tighten the two bolts that hold bracket (8) to the top of cover (6). This puts the bracket in correct alignment.

d. Tighten the two bolts that hold bracket (8) to the governor.

e. Check the governor terminal shaft for free movement, see Step 6.

CHECK TERMINAL SHAFT MOVEMENT

6. Use a 7/16" wrench and move the governor terminal shaft several times in the "FUEL ON" direction and release it. The terminal shaft must return completely to the "FUEL OFF" position each time. If the terminal shaft does not return, binding can be the result of parts not in correct alignment.

If the terminal shaft is binding, loosen the cover bolts, make an alignment of the cover again, then tighten the bolts again. Check for binding again with the above procedure. If this does not correct the binding, loosen the governor base to drive housing bolts. Move the governor and tighten the bolts again. Check for binding again with the above procedure.

NOTE: If the governor terminal shaft is binding after the above procedure, loosen the bolts for the fuel control linkage cover. Then loosen the bolts that hold the governor drive housing in position and move the housing to make an alignment of the cover bolt holes. Tighten all of the bolts again and check for terminal shaft binding.

CORRECT GOVERNOR OIL LEVEL

7. It is necessary to prime the governor. Remove the oil fill plug from the governor top cover. Add 1.8 liter (2 U.S. quarts) of clean engine oil to the governor before the first engine start up. Replace the plug in the top cover and tighten.

3161 Governor With Torque Rise

6V3139 Timing and Fuel Setting Tool Group.

5P4814 Collet.6V3075 Dial Indicator (metric).5P7263 Contact Point, 76.2 mm (3.00 in.) long.

FT1819 Governor Torque Arm Tool.

1. Put the governor in position on the engine as in Steps 1 through 3 for 3161 Standard and Generator Set Governors.

FUEL SETTING COVER
1. Synchronizing pin. 2. Plug. 3. Plug.

2. Remove plugs (2) and (3) from each side of the fuel setting cover.

3. Remove synchronizing pin (1) from the fuel setting cover and remove the washer from it. Install synchronizing pin (1) in the threaded hole for plug (2). Tighten the synchronizing pin (1) in position.

MOVE FUEL CONTROL LINKAGE AGAINST SYNCHRONIZING PIN
4. FT1819 Governor Torque Arm Tool.

4. Use FT1819 Governor Torque Arm Tool (4) to move and hold the governor terminal shaft in the "FUEL ON" direction. This puts the fuel control linkage stop lever against the end of synchronizing pin (1). The FT1819 Governor Torque Arm Tool is to be attached only with the engine shut down.

NOTE: A torque wrench and a 7/16 in. crowfoot wrench can be used to move the terminal shaft in the "FUEL ON" direction. Hold the governor terminal shaft and fuel control linkage against the synchronizing pin with 10 N·m (90 lb. in.) force to give an accurate dial indicator setting.

INSTALL DIAL INDICATOR
5. Manual fuel shutoff lever. 6. 6V3075 Dial Indicator with the 5P7263 Contact Point in the 5P4814 Collet. 7. Bolt.

5. Put 6V3075 Dial Indicator (6) with the 5P7263 Contact Point in the 5P4814 Collet. Install the dial indicator and collet in the threaded hole as shown. When the contact point seats against the fuel stop lever, slide the dial indicator in or out until the indicator reads zero. Now tighten the collet just enough to hold indicator at this position.

6. Remove tool (4) from the governor terminal shaft. Make sure the terminal shaft returns to the "FUEL OFF" position.

7. Remove bolt (7) and manual fuel shutoff lever (5).

8. Turn synchronizing pin (1) back out a minimum of 25 mm (1 in.) or remove it completely.

ENGAGE GOVERNOR ZEROING PIN

9. The zeroing pin is engaged to hold the governor at a fixed position for setting the adjustable pin lever to synchronize the governor travel with the engine fuel control linkage travel. This pin is to be engaged only with the engine shut down.

Put a 5/32 inch hex wrench in the governor zeroing pin, push in and turn it counterclockwise until the roll pin locks squarely behind the bracket.

10. Install FT1819 Governor Torque Arm Tool (4) again to turn and hold the governor terminal shaft and linkage against the zeroing pin.

ADJUSTABLE PIN SETTING

11. With a 1/2 in. by 3/8 in. drive socket on a 12 in. extension and ratchet put the socket and extension between the cover and housing. Put the socket on the bolt that holds the adjustable pin lock and loosen the bolt.

NOTE: Later pins use a hex socket head bolt for use with 3/8 in. drive sockets with a 1/4 in. hex bit.

Move the ratchet and extension up or down until the dial indicator reads zero ± 0.13 mm while the terminal shaft is held in the "FUEL ON" direction against the governor zeroing pin.

Tighten the bolt on the lock to a torque of 25 ± 7 N·m (18 ± 5 lb. ft.).

Move tool (4) in the "FUEL OFF" position and release. The dial indicator must return to zero each time. If it does not, do the above procedure again.

RELEASE GOVERNOR ZEROING PIN

12. Remove tool (4) from the governor terminal shaft.

13. Release the governor zeroing pin. Push on the hex wrench and turn it clockwise until the roll pin unlocks from the bracket. Release the hex wrench and the spring will return the pin to the disengaged position. Remove the hex wrench.

14. Turn synchronizing pin (1) in all of the way and tighten it (install the pin as in Step 4 if it was removed). Use tool (4) to hold the fuel control linkage against synchronizing pin (1) as in Step 5. Without change to the dial indicator position, make sure the reading is zero to indicate correct fuel control linkage setting.

REMOVE SYNCHRONIZING PIN AND DIAL INDICATOR
1. Synchronizing pin. 6. 6V3075 Dial Indicator.

15. Remove 6V3075 Dial Indicator (6) and the collet. Remove synchronizing pin (3) and install it with the washer to hold the fuel setting cover in position.

16. Install the two plugs on each side of the fuel setting cover.

17. Follow Steps 4 through 7 for 3161 Standard and Generator Set Governors to install the cover, bracket and check for free movement of the fuel control linkage and governor.

Governor Adjustments

Droop Setting - Internal Adjustment

INTERNAL DROOP ADJUSTMENT
1. Locknut.

When the position of the droop pivot pin (internal or external) is changed on the terminal lever, the percent of governor droop changes.

To change the droop pivot pin setting on governors not equipped with an external adjustment lever, the governor top cover must be removed.

The droop pivot pin is fastened to the terminal lever with locknut (1). With the nut loosened, the pivot pin can be moved from minimum droop to maximum droop. It is shown here in the minimum droop position.

The terminal shafts are clamped in the ends of the terminal lever by two bolts. A line can be drawn through the center of the two bolt heads and used for reference in adjusting the droop pivot pin position.

When the pivot pin and nut is moved near the reference line as shown, the governor is set for minimum droop. As the pivot pin and nut are moved farther away from the reference line, the droop is increased. When the pivot pin and nut are moved to the farthest point away from the reference line the governor is set for maximum droop.

Droop Setting - External Adjustment

On the 3161 Generator Set Governor, the internal droop pivot pin locknut must be kept loose enough to be moved by the external droop adjustment lever. The external droop adjustment lever is held in place with a bolt which retains the droop setting.

EXTERNAL DROOP ADJUSTMENT
1. Bolt.

To change the droop setting, loosen the adjustment lever bolt (1) and move the lever down to decrease droop, and up to increase droop.

Droop Setting Check

After an adjustment has been made to the droop pivot pin (internal or external), the setting can be checked by alternately loading and checking the high idle speed.

As this procedure is performed, the high idle screw will probably have to be adjusted. The full load speed of the engine will also adjust upward or downward.

As droop is decreased, full load speed is increased, high idle speed is decreased. The greater the percent droop, expect the full load speed to decrease, and the high idle speed to increase. Therefore high idle speed should be adjusted to set the full load speed at the correct rpm.

Compensation Needle Valve Adjustment

After the engine has started and is under governor control, open the needle valve (turn it counterclockwise) until governor operation just becomes unstable (starts to hunt), then turn the needle valve in until engine speed has stability. Let the governor and engine get to operating temperature by operating a minimum of one-half hour. After the engine and governor are at the operating temperature, again check for stable operation. Adjust as necessary. DO NOT fully close the needle valve. This can cause excessive overshoot on startup, or load rejection.

NEEDLE VALVE ADJUSTMENT

With the engine at normal operating temperature and no load, operate the engine at low idle speed. Open the governor compensation needle valve and let the governor increase and decrease engine speed (hunt) for a minimum of 30 seconds to remove air from the system. If the governor does not hunt, rapidly move the speed control shaft to change governor stability.

After 30 seconds and the air is removed from the system, turn the needle valve in (clockwise) until the engine runs smoothly.

With the engine running at medium (mid) speed, load the engine (at least one-quarter load) to find the stability of the setting. Quickly remove the load. A slight overshoot of speed is ideal, as it reduces response time. The engine speed should return to smooth steady operation. If it does not have a slight overshoot and return to a smooth steady operation, adjust the needle valve and repeat the above procedure.

Governor terminal shaft "jiggle" or surge is an indication of:

1. Too little compensation (needle valve out too far);

2. Torsional vibration (pulsing);

3. Improperly aligned governor drive spline;

4. A binding or loose fuel control mechanism.

Low And High Idle Adjustments

NOTE: Make sure the engine fuel setting is correct before low and high idle adjustments are made. See the engine TESTING AND ADJUSTING Service Manual for the fuel setting procedure.

LOW IDLE ADJUSTMENT
1. Low idle stop screw. 2. Plate.

Low and high idle speed stop screws are on the left side of the governor case, and are adjusted from the outside of the governor.

The low idle speed stop screw is not covered, and can be adjusted without breaking the wire seal (wire and seal not shown).

The high idle speed stop screw is covered by plate (2). The plate is held to the governor case with two wire lock bolts. Install a wire and seal on the high idle speed adjustment cover bolts to prevent tampering.

A 1/8 inch hex wrench is used for turning both low and high idle speed stop screws.

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The engine may overspeed due to improper reassembly or adjustment, which could result in personal injury, loss of life, and/or property damage. Be prepared to stop the engine by activating the emergency air shut off or closing the air inlets.

HIGH IDLE ADJUSTMENT
3. High idle stop screw.

To increase the engine low idle speed, turn screw (1) clockwise.

Turn high idle speed stop screw (3) clockwise to decrease high idle speed.

INSTALL COVER
2. Plate.

When the high and low idle speeds are adjusted to the specifications given in the Fuel Setting and Related Information Fiche, install the plate and the two bolts. Put a seal wire through the holes in the bolt heads and install the seal as required on other Caterpillar fuel systems.

Torque Rise Setting (On 3500 Series Engines)

6V3139 Timing and Fuel Setting Tool Group.

5P4814 Collet.6V3075 Dial Indicator (two required).5P7263 Contact Point, 76.2 mm (3.00 in.) long.

FT1819 Governor Torque Arm Tool.9S228 Rack Position Tool Group.

9S225 Bracket Assembly.

3S3269 Contact Point, 25.4 mm (1.00 in.) long.

1. Look in the Fuel Setting and Related Information Fiche to find the correct engine fuel setting, torque rise and full load.

In the past only "static fuel setting" was listed in the Fuel Setting and Related Information Fiche for the 3500 Series Engines. This fuel setting was "maximum travel" and listed as "static fuel setting."

On 3500 Series Engines equipped with a 3161 Standard or Generator Set Governor, the fuel setting procedure has not changed. The fuel setting screw is used to set the "maximum travel" but the specification in the Fuel Setting and Related Information Fiche has changed and is shown as "full load."

On 3500 Series Engines equipped with 3161 Governors with torque rise there are two static fuel settings. One is torque rise, which is maximum travel, and is set with the fuel setting screw.

The second setting is full load, which is a "reference position" where the fuel control linkage is held while the torque rise cam is adjusted. This is a temporary setting set with the synchronizing pin. This setting is shown in the Fuel Setting and Related Information Fiche as "full load."

Torque rise fuel setting is greater than full load fuel setting, thus making the torque rise setting the "maximum travel" setting of the fuel control linkage.

INSTALL SYNCHRONIZING PIN
1. Synchronizing pin. 2. Plug. 3. Plug.

2. Remove plugs (2) and (3) from each side of the fuel setting cover.

3. Remove synchronizing pin (1) from the cover and remove the washer from it. Install synchronizing pin (1) in the threaded hole for plug (2) and tighten it.

MOVE FUEL CONTROL LINKAGE AGAINST THE SYNCHRONIZING PIN
4. FT1819 Governor Torque Arm Tool.

4. Use tool (4) to move and hold the fuel control linkage in the "FUEL ON" direction against the synchronizing pin.

INSTALL DIAL INDICATOR
1. Synchronizing pin. 5. 6V3075 Dial Indicator. 6. Fuel setting cover.

5. Put dial indicator (5) with the 5P7263 Contact Point in the 5P4814 Collet. Install dial indicator (5) and the collet in the threaded hole for plug (3). When the contact point seats against the fuel stop lever, slide the dial indicator in or out until it reads zero. Now tighten the collet just enough to hold dial indicator (5) at this position.

REMOVE GOVERNOR TOP COVER
7. Cover. 8. Gasket.

6. Remove the bolts that hold cover (7) in position. Lift cover (7) off the governor and remove gasket (8).

INSTALL DIAL INDICATOR
9. 6V3075 Dial Indicator. 10. 9S228 Bracket Assembly. 11. 3S3269 Contact Point. 12. Bolt.

7. Install dial indicator (9) on the top of the governor housing with bracket assembly (10) as follows:

Use a top cover bolt with three washers (as spacers under the bolt head) on it and put the bolt through the fixed diameter hole in the bracket. Fasten the bracket to the left side of the housing in the second threaded hole from the front. Put the dial indicator in the adjustable hole in the bracket assembly and position it so the indicator contact point (11) rests on the bolt head (12) of the torque control lever.

8. Check to make sure the cam follower is on the base circle of the governor torque rise cam. See Systems Operation section for a description of the base circle.

9. Move dial indicator (9) until it reads zero and fasten it in place.

10. Turn the synchronizing pin out of the engine front drive housing a minimum of half-way. As the synchronizing pin is backed out, dial indicator (5) will follow the fuel control linkage movement until the fuel control linkage stop lever contacts the fuel setting screw. Dial indicator (5) now shows the torque rise fuel setting. Make sure the torque rise fuel setting is correct. If not, an adjustment is necessary.

11. Look in the Fuel Setting and Related Information Fiche for the full load setting for the engine you are adjusting.

12. Turn the synchronizing pin in until dial indicator (5) reads the full load fuel setting. The full load setting is a reference position and is a temporary setting used to adjust the torque rise cam position.

The purpose of this procedure is to hold the fuel control linkage at the full load setting while the torque rise cam is adjusted.

13. Dial indicator (9) must read 1.00 ± 0.05 mm, if it does not, an adjustment is needed. Loosen the bolt that holds the cam enough so the cam can be moved, but keep the bolt tight enough to provide a small drag on the cam.

14. Slide the cam to cause the torque control lever and dial indicator contact to lift 1.00 ± 0.05 mm.

15. Tighten the bolt while the cam is held in place. This adjustment of 1.00 ± 0.05 mm positions the torque control lever so the torque rise (additional fuel) begins to occur at the correct engine speed.

TORQUE RISE CAM ADJUSTMENT

16. Check the cam position by lifting and lowering governor torque arm tool (4) on the terminal shaft. The dial indicator (9) should return to the 1.00 ± 0.05 mm setting. If it does not, repeat the adjustment procedure and check again.

The following is an example of this torque rise cam setting. If the engine were running at a rated 1800 r/min with a load, the fuel control linkage would be at full load position and the torque rise cam follower would have lifted 1.00 mm. Torque rise would not have occurred, but would be at the starting point. Should more load be added, the engine speed would decrease. As the speed drops, the terminal shaft and torque rise cam will move and lift the torque rise pilot valve lever beyond the 1.00 ± 0.05 mm set point. This will lift the pilot valve and provide additional fuel to the engine and give torque rise greater than the natural torque rise of the engine.

As more load is applied, engine speed will decrease. The fuel control linkage will continue to move in the "FUEL ON" direction, increasing the fuel rate until the fuel control linkage stop lever contacts the fuel setting screw. This is the torque rise fuel setting, and is maximum travel.

17. With the torque rise cam setting made, remove the dial indicator and bracket assembly and install the gasket and top cover on the governor.

NOTE: Make sure the air fuel ratio control limit lever is engaged correctly in the notch of the governor housing before the top cover is installed.

18. Remove dial indicator (5) and the collet. Remove synchronizing pin (1) and install it with the washer to hold the fuel setting cover.

19. Install the two plugs on each side of the fuel setting cover.

Auxiliary Controls

Electric Shutdown

ELECTRIC SHUTDOWN ASSEMBLY

The shutdown lever in the electric shutdown assembly is adjusted up or down to keep the shutdown/limit rod in the correct position until the shutoff solenoid is activated.

1. Install the gasket and electric shutdown on top of the governor. Tighten the bolts to 10 N·m (90 lb.in.).

2. Remove the cover, manual shutdown or pressure shutdown, if so equipped, from the top of the electric shutdown assembly.

3. Turn the adjustment screw until the shutdown plunger is even with the top of the gasket for the cover or other shutdowns.

4. Install the cover, manual shutdown or pressure shutdown, if so equipped.

Pneumatic Speed Setting Control Adjustments

The pneumatic speed setting control has two adjustments. One is the speed range bellows adjustment made by turning the bellows (1) inside the bellows housing to increase or decrease the speed range.

PNEUMATIC SPEED SETTING CONTROL
1. Bellows. 2. Plug over low idle adjustment screw.

The other is the pneumatic speed level ratio (bias spring) adjustment, made by removing plug (2) and turning the adjustment screw with a 1/8 inch hex wrench.

Pneumatic Speed Level Ratio Adjustment

ADJUSTMENT OF LOW IDLE

When the speed level adjusting screw is turned the low speed setting of the pneumatic control is changed.

With the plug removed, put a 1/8 in. hex wrench in the hole until it engages with the adjustment screw. Turn the screw clockwise to decrease the low idle setting. Turn the screw counterclockwise to increase the low speed setting.

Feedback Spring

To use the pneumatic speed setting control with different air pressure ranges and engine speed settings the feedback spring must be changed.

REMOVE OIL LINE
1. Tube assembly. 2. Plate.

1. Remove tube assembly (1) and plate (2) from the governor.

REMOVE PLUG
3. Plug.

2. Install one of the bolts for plate (2) into plug (3) as shown and pull plug (3) out of its bore.

FEEDBACK SPRING AND SPEED SETTING PISTON POSITION
3. Plug. 4. Piston. 5. Spring.

3. With plug (3) out of the bore, speed setting piston (4) and feedback spring (5) can be lifted out of the bore with a magnet.

4. Find the correct feedback spring to use for the air pressure range and engine speed rating from the pneumatic speed control spring chart.

5. Install spring (5) in the bore over the speed setting rod.

6. Place piston (4) over spring (5) and push it down into the counterbore.

7. Install a new seal on plug (3), if the original seal is not in good condition.

8. Push plug (3) down in the bore and remove the bolt.

9. Put plate (2) in position, and install the three bolts and tighten them to 10 N·m (90 lb. in.).

10. Install tube assembly (1) on the governor.

Speed Range Bellows Adjustment

The bellows is made off-center (eccentric) to the top flange area. The bottom of the bellows has a swivel pin that engages the hole in the end of the speed setting lever. The swivel pin is set off-center (eccentric) to the bottom of the bellows but is in line with the center of the air inlet port in the top of the flange.

SPEED SETTING BELLOWS AND LEVER

There is an index mark (notch) 0.76 mm (.030 in.) deep on the outer face of the bellows flange. The index mark is approximately mid range position when it is turned to the front of the governor (when facing the governor name plate).

SPEED SETTING CONTROL
1. Air inlet port. 2. Feedback spring. 3. Pivot.

Control air pressure enters the bellows through air inlet port (1) at the top of the flange. Control air pressure expands the speed setting bellows, which pushes down on the lever at the left of pivot (3), raising the right end of the lever against feedback spring (2). The force of the feedback spring is marked on the end of the spring.

When the bellows is turned, the eccentric changes the position of the bellows on the speed setting lever. This changes the length of the lever arm. The lever arm is the distance from pivot (3) to the outer edge of the bellows.

When the bellows is turned with the index mark to the right side of the governor (counterclockwise as seen from governor nameplate), the bellows moves closer to the pivot pin. This makes the lever arm shorter and lowers engine speed for a given amount of air pressure.

LOWER SPEED SETTING

HIGHER SPEED SETTING

With the index mark to the left side of the governor (as seen from governor nameplate), the bellows is farther away from the pivot pin. The lever arm is now longer and engine speed is increased for a given amount of air pressure.

CONNECT PRESSURE REGULATOR AND GAUGE ASSEMBLY

Before the control adjustment can be made, install a pressure regulator and gauge assembly in the control air supply line. Also, connect a tachometer with good accuracy to the engine.

ADJUST AIR PRESSURE

Start the engine and let it run at the low idle speed setting as given in the Fuel Setting and Related Information Fiche (for example, 600 rpm).

Turn the air pressure regulator and slowly increase and then decrease control air pressure. Engine speed must increase and decrease smoothly and return to the original speed setting (600 rpm).

Return the control air pressure with the regulator and gauge assembly to 0 kPa (0 psi).

NOTE: The governor is shown off engine for photographic purposes. The pneumatic speed setting control adjustments must be made with the governor on the engine, and with the engine running.

Adjust the pressure regulator and apply the required low idle air pressure to the speed setting bellows [for example 76 kPa (11 psi)].

ADJUST LOW IDLE SPEED

Turn the speed level adjusting screw with a 1/8inch hex wrench and bring the engine speed to the desired low idle speed setting (for example, 600 rpm).

Increase the control air to the high idle air pressure [for example 407 kPa (59 psi)] for the engine high idle speed setting (for example, 1980 rpm).

If the speed is too high, lower the air to the low idle air pressure setting [76 kPa (11 psi)].

ADJUST BELLOWS

Loosen the two bolts that hold the bellows clamp down. With a 3/4 inch wrench, rotate the bellows in a counterclockwise direction (as seen from governor nameplate). Again adjust the low idle speed setting back to 600 rpm at low air pressure [76 kPa (11 psi)], turn the speed level adjusting screw clockwise.

If the speed is too low, lower the air to the low idle air pressure [76 kPa (11 psi)].

Loosen the two bolts that hold the bellows clamp down. With the 3/4 inch wrench, turn the bellows in a clockwise direction (as seen from governor nameplate) and again adjust the low idle speed setting back to the 600 rpm at low air pressure [76 kPa (11 psi)].

Again, increase the control air to the pressure required for the high idle speed. If the speed range is still incorrect, repeat the above steps until the correct low idle speed and high idle speed setting is reached for each required air pressure. Make sure to tighten the bellows clamp bolts after the speed setting is correctly adjusted.

Check the pneumatic speed setting control for external leaks. Remove the air pressure regulator and pressure gauge assembly from the control air supply line.

Air Fuel Ratio Control Adjustments (On 3500 Series Engines)

ADJUSTMENT OF FUEL LIMIT LEVEL

There are three adjustments for the air fuel ratio control. One is the fuel limit level adjustment screw, the second is gain rate cam slide adjustment. The third is the cocking level setting. These last two are factory set and do not require adjustment. Any change to their settings will require the governor to be put on a test bench and correct settings made to test bench procedures.

To adjust the fuel limit level, remove the plug from the right front corner of the top cover. Put a 3/16 inch hex wrench through the hole in the top cover until it engages the fuel limit level adjustment screw. Install and zero the dial indicator on the side of the engine front drive housing for checking fuel setting.

For an initial setting, turn the limit level screw in until it stops, then back it out 10 turns (about mid-travel). Start the engine and load it enough to generate boost of 10 inches of mercury to cock the control. Disconnect the air pressure line from the control to the manifold.

Rapidly move the speed control shaft in the speed increase direction. The dial indicator will go up to the fuel limit position, pause momentarily, then drop back. Do this several times and read the dial indicator during each pause. Or, load the engine until the dial indicator stops. Where the dial indicator pauses or stops, is the limit travel setting of the control. Turn the limit level screw until the dial indicator agrees with the specifications given in the Fuel Setting and Related Information Fiche.

When the adjustment is correct, correct the air pressure line from the control to the manifold. Remove the hex wrench and install the plug in the top cover. Remove the dial indicator from the front drive housing.

Pneumatic Mid-Speed Control (On 3500 Series Engines)

PNEUMATIC MID-SPEED CONTROL ADJUSTMENT

The control cylinder mounts on the front of the governor. An adjustable lever is fastened on the speed setting control shaft. The cylinder rod is spring-actuated (extended) and air-retracted. With the cylinder retracted, and the speed setting shaft in the fuel shutoff position, set the lever at 60 degrees below the horizontal centerline. When the cylinder rod is extended the lever will move the speed setting shaft in the "FUEL ON" direction to 45 degrees below the horizontal centerline. If necessary, adjust the lever to achieve a 1400 rpm engine speed.