Cummins/Onan 6.5 HGJAE Generator Set

⚠ Voltage/frequency-sensitive equipment may be damaged by power line frequency variations; disconnect them before adjustments.

Tools: Variable load bank up to 7 kW, Frequency meter (within 0.3%), Voltmeter (within 0.5%), AC ammeter

1. Warm up the genset for at least 5 minutes at 1/2 to 3/4 rated load with the choke fully open.
2. Adjust frequency close to the Table 8-3 value with the speed adjusting nut.
3. With the engine warm, remove all loads and adjust the idle stop screw to 51-53 Hz (60 Hz genset) or 41-43 Hz (50 Hz genset).
4. Let the throttle lever go and recheck/adjust No-Load frequency to Table 8-3; bump the governor arm to check stabilization.
5. Connect rated load; if droop is out of spec move the governor spring hook one or two notches and recheck.
6. Confirm the governor does not hunt under the loading sequence.

Tools: Socket wrench, Feeler gauge, Torque wrench

1. Adjust when the engine is at room temperature.
2. Remove the spark plugs so the engine is easier to turn over.
3. Use a socket wrench on the generator pulley nut to turn the engine clockwise; remove the snap-in cover.
4. Remove the valve covers with rags in place to catch oil.
5. Turn engine until No. 2 intake valve is at max lift; adjust No. 1 intake valve lash.
6. Turn engine until No. 2 exhaust valve is at max lift; adjust No. 1 exhaust valve lash.
7. Turn engine until No. 1 intake valve is at max lift; adjust No. 2 intake valve lash.
8. Turn engine until No. 1 exhaust valve is at max lift; adjust No. 2 exhaust valve lash.
9. Secure valve covers using new gaskets and torque cover screws to 5.5 lb-ft (8 N-m).
10. Replace the spark plugs and pulley nut cover.

Tools: Battery terminal puller, Torque wrench

1. Loosen the governor shaft nut by turning it clockwise and remove the arm.
2. Use a battery terminal puller to break the taper fit of the shaft in the arm hub.
3. Reattach arm and hub making sure the pins and holes engage; thread the shaft nut on counterclockwise.
4. Check free rotation of the arm and let the governor spring take up all play; linkage must push throttle against the wide open throttle stop.
5. Torque the shaft nut to 8 lb-ft (11 N-m) counterclockwise.
6. Push the governor arm down and check for binding or interference.

Tools: Feeler gauge, Torque wrench

1. Bar the engine until the lands on the flywheel directly face the coils.
2. Place a 0.012 inch (0.03 mm) thick feeler gauge between the coil and the land.
3. Hold the coil tight against the feeler gauge and land and torque the two mounting bolts to 5 lb-ft (7 N-m).

⚠ The high pressure spray from a hydraulic line can penetrate the skin, leading to possible blood poisoning.

Tools: Two wrenches

1. Provide enough slack in connected hoses to prevent strain due to pump movement.
2. Support, restrain and protect hydraulic hose to prevent chaffing.
3. Do not bend hose tighter than the hose manufacturer recommends.
4. Use wide-sweep 90-degree fittings.
5. Always use two wrenches when tightening hydraulic fittings.
6. Install an SAE Class 4 filter (10 micron) in the system.
7. Fill the reservoir and crank the engine with spark plug cables disconnected until oil reaches the pump.
8. Purge air by running the genset a few seconds at a time until metallic noise stops.

1. Repair any damage to and seal all holes in the vapor-tight, fire-resistive barrier between genset and coach interior.
2. Make sure all mounting bolts and brackets are secure.
3. Make sure all battery, AC output, control, exhaust and fuel connections are proper and in good repair.
4. Perform the service checklist before placing the genset in service.

⚠ Running the genset without oil in the hydraulic pump will destroy the pump.

⚠ The high pressure spray from a leak or fitting in a hydraulic line can penetrate the skin, leading to possible blood poisoning.

Tools: Torque wrench

1. Apply molybdenum disulfide paste or equivalent to the shaft spline.
2. Torque the two flange screws to 20 lb-ft (26 N-m).
3. Do not start the genset before the pump is connected and filled with oil.

⚠ Arcing at battery terminals can ignite battery gas causing severe personal injury.

⚠ Gasoline and LPG are flammable and explosive and can cause severe personal injury or death.

⚠ LPG sinks and can accumulate in explosive concentrations.

1. Disconnect all battery cables (negative first) at the battery terminals.
2. Disconnect the negative and positive battery cables at the genset.
3. Disconnect the wiring connectors for remote control and remote fuel pump.
4. Disconnect the generator AC output wires and conduit from the junction box.
5. Disconnect the exhaust tail pipe.
6. Gasoline models: disconnect the fuel line(s) and securely plug the ends.
7. LPG models: close the fuel shutoff valve(s), move the vehicle outside and away from below-grade spaces, purge LPG, then disconnect and plug.

⚠ Contact with used engine oil can cause cancer or reproductive toxicity.

⚠ Crankcase pressure can blow hot engine oil out the fill opening causing severe burns.

1. Place a pan underneath the oil drain hose and filter; run then stop the engine when warm.
2. Remove the oil fill cap, open the oil drain valve, let all oil drain, then close the drain valve.
3. High Pressure LPG gensets: drain accumulated sludge by opening the sludge drain valve, then re-close.
4. Spin off the old oil filter and wipe the mounting surface; remove the old gasket.
5. Apply a film of oil to the filter gasket and spin the new filter on by hand until the gasket touches; then turn 1/2 to 3/4 turn.
6. Refill with 2 quarts (1.8 l) of oil; check and add or drain as necessary.
7. Dispose of used oil and oil filter per local environmental regulations.

⚠ Crankcase pressure can blow hot engine oil out the fill opening causing severe burns. Always stop the genset before removing the oil fill cap.

1. Park the vehicle on level ground and shut off the genset.
2. Unscrew the oil fill cap and wipe oil off the dipstick; screw the cap back on, remove it and check level.
3. Add or drain oil as necessary; keep level between FULL and ADD marks.
4. Recheck the level in a few minutes and screw the oil fill cap back on securely.

⚠ Hot muffler can cause severe burns

Tools: 7/16-inch 8-point socket, 3-inch extension, swivel section, 6-inch extension, 3/8-inch drive socket wrench

1. Remove the cleanout plug
2. Start and load generator set to near full power for about 5 minutes to expel soot
3. Stop generator set, allow muffler to cool, reinstall plug

⚠ A hot muffler can cause severe burns. Let the muffler cool down before removing or installing cleanout plugs or screens.

Tools: 7/16 inch eight point socket wrench

1. Locate the cleanout plug by hand and seat a 7/16 inch, eight point, 3/8 inch drive socket with extension on the plug.
2. Remove the plug.
3. Start and load the genset to near full power and run about five minutes to expel soot.
4. Stop the genset, allow the muffler to cool, then reinstall the plug.