D379, D398, D399 INDUSTRIAL AND GENERATOR SET ENGINES Caterpillar

(22)Woodward UG8 Governor

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Be sure the engine cannot be started while work is being done. This is very important when the engine is equipped with an Automatic Start-Stop System.

1. Move the governor control lever to the shut-off position.

2. Shut off the fuel tank fuel supply valve.

3. Disconnect the ground cable from battery.

4. Disconnect the governor linkage from the governor.

5. Disconnect the governor synchronizing motor wires.

6. Remove the governor from the engine.

7. Remove the governor cover.

8. Turn the governor upside down and drain the oil.

9. Flush the governor with clean nonflammable solvent.

10. Install the governor on the engine.

11. Fill the governor, with clean oil, to the FULL mark on the sight gauge. See Lubrication and Maintenance Chart for proper oil.

12. Connect the governor linkage.

13. Connect the ground cable to the battery.

Bleeding the Governor

1. Start the engine and allow the engine to reach normal operating temperature.

2. Loosen the nut on the side of the governor which holds the compensation adjusting pointer.

3. Manually move the pointer to the extreme upper position and tighten the nut. This will allow the governor to be purged of air.

4. Remove the plug from the base of the governor.

5. Using a wide blade screwdriver, engage the wide shallow screwdriver slot and turn the needle valve 3 or more turns counterclockwise.

6. Allow the engine to surge for approximately 30 seconds.

7. Loosen the nut and move the compensation adjusting pointer to the extreme downward position. Tighten the nut.

8. Slowly turn the needle valve (wide shallow slot) clockwise until the surging stops.

9. It should now take less than one turn from this point to close the valve completely.

10. Open the valve to the same position where the surging had stopped.

11. Manually move the governor linkage to disturb the engine speed.

If the engine speed stabilizes, and the needle valve is only 1/2 to 3/4 turn open, the governor is properly adjusted. Install the base plug.

If more than a 3/4 turn is required to stop the engine from surging, proceed with the following steps.

12. Raise the pointer two divisions on the pointer scale.

13. Engage the wide shallow slot and turn the needle valve counterclockwise 3 or more turns.

14. Allow the engine to surge approximately 30 seconds.

15. Gradually turn the needle valve clockwise until surging just stops.

16. Note the portion of a turn required to close the needle valve.

17. Open the valve exactly to the same position surging stopped.

18. Manually move the governor linkage to disturb the engine speed. The engine speed should stabilize with the needle valve opened 1/2 to 3/4 turn.

19. A valve opened less than 1/2 of a turn produces a slow response to load changes. A valve opened more than 3/4 of a turn produces excessive speed response to load change. If the engine does not stabilize between 1/2 to 3/4 turn open, raise the pointer two divisions and repeat steps 12 through 19.

20. When the engine speed stabilizes, install the base plug.

(23)Fuel Priming Pump

Early D379 or D398

Lubricate 1 fitting.

Early D399

Lubricate 2 fittings.

(24)Crankshaft Coupling

D399 only

1. Rotate the crankshaft until the two lubricating plugs are 45° from horizontal.

2. Remove the lower plug.

3. Remove the upper plug and install a grease fitting.

4. Lubricate with grease until the grease appears at the lower hole.

5. Remove the fitting, wipe off the excess grease, and install both plugs.

(25)Shut Off Control Lever

Lubricate 2 fittings.

(26)Tachometer Drive

Lubricate 1 fitting.