Cummins/Onan RV Generator Set Generator Set

⚠ For accurate adjustments, valve lash must be adjusted when the engine is at room temperature.

Tools: Feeler gauge, Wrench

1. Remove the spark plug to make it easier to turn the engine.
2. Remove the cylinder head cover and confirm the timing point at TDC of compression stroke.
3. Measure intake and exhaust valve clearance with a thickness gauge.
4. Fix the valve adjusting screw and loosen the valve lock nut.
5. Rotate the adjusting screw to the specified clearance.
6. Hold the screw and tighten the valve lock nut, then recheck clearance.

⚠ Make certain no flammable fumes are present and the area is well ventilated.

Tools: Inline spark tester

1. Remove the spark plugs.
2. Reconnect the spark plug cables.
3. Ground the side electrodes to bare metal on the engine.
4. Crank the engine and look for spark across the plug.

⚠ EXHAUST GAS IS DEADLY! Do not operate the generator set where exhaust can accumulate.

Tools: Thermocouples, Load bank

1. Complete a representative installation.
2. Set up a load bank to run the generator set at rated full load.
3. Conduct the test with ambient air between 16 C and 38 C (60 F and 100 F).
4. Measure inlet and ambient temperatures with thermocouples not heavier than 0.21 mm2.
5. Close all compartment doors and run at full load at least an hour, recording every 15 minutes.

⚠ Too little oil can cause severe engine damage.

1. Refill with 2.7 qts (2.4 liters) of oil.
2. Check and add or drain oil as necessary.
3. Recheck level after a few minutes; oil fills slowly.

⚠ Stop the generator set before removing the oil fill cap; crankcase pressure can blow hot oil out.

1. Place a pan underneath the oil drain hose.
2. Run and then stop the engine when it is warm.
3. Remove the oil fill cap and open the oil drain valve.
4. Let all oil drain from the engine, then close the drain valve.
5. Refill with 2.7 qts (2.4 liters) of oil and check level.
6. Dispose of the used oil in accordance with local environmental regulations.

⚠ Always stop the generator set before removing the oil fill cap.

1. Park the vehicle on level ground and shut off the generator set.
2. Remove the oil fill cap and wipe oil off the dipstick.
3. Reinsert without screwing in the dipstick, then remove to check level.
4. Add or drain oil as necessary, keep level between FULL and ADD marks.
5. Screw the oil fill cap back on securely.

⚠ A hot muffler can cause severe burns; let the muffler cool before removing or installing cleanout plugs.

1. Remove the six screws from the blinds, then remove the blinds.
2. Remove the cleanout plug.
3. Start and load the generator set to near full power for about 5 minutes.
4. Stop the generator set, let the muffler cool, and reinstall the plug.
5. Install the blinds back in place.

⚠ Do not disconnect battery cables while the generator set is running.

Tools: Battery terminal puller

1. Keep the battery case and terminals clean and dry and the terminals tight.
2. Remove the battery cables with a battery terminal puller.
3. Identify positive and negative terminals; remove negative cable first and reconnect it last.

Tools: Spark plug socket wrench

1. Refer to the Periodic Maintenance section for scheduled replacement.
2. Screw the spark plug in by hand using a spark plug socket wrench.
3. Fully tighten the spark plug until pressed against the washer.

⚠ No filter cartridge or a damaged cartridge may cause dust to enter the engine and rapid erosion.

1. Remove the front access cover.
2. Rotate and remove the air filter cover.
3. Pull the air cleaner element out of the air cleaner housing.
4. Clean sealing surface and install the new air cleaner element.
5. Return the air filter cover and turn and tighten as indicated.
6. Re-install the front access cover.

⚠ Ventilate battery area; always disconnect the negative cable first and reconnect it last.

1. Disconnect all battery cables, negative cable first, at the battery terminals.
2. Disconnect the negative and positive battery cables at the generator set.
3. Disconnect the wiring connectors for remote control.
4. Disconnect the generator AC output wires and conduit.
5. Disconnect the exhaust tail pipe.
6. Disconnect and plug the fuel line(s) for gasoline or close LPG shutoff valves and purge.

⚠ High electrical currents, strong arcing and moving parts; keep fingers away from the pinion gear.

Tools: Heavy jumper cable, Vice

1. Secure the motor assembly in a vice after removal.
2. Connect the motor terminal on the solenoid to the positive terminal of a 12 V battery.
3. Briefly touch the mounting flange on the motor with the negative cable.
4. If the motor does not spin up quickly, replace the motor/solenoid assembly.
5. If it spins up, disconnect the motor lead and remove the two solenoid mounting nuts to replace the solenoid.