Cummins/Onan 4.0 KY Generator Set

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

⚠ Used engine oil can cause cancer or reproductive toxicity

Tools: 14 mm socket

1. Run the generator set under load until at operating temperature, stop it, disconnect negative battery cable
2. Remove the oil fill cap
3. Place a pan under the oil drain plug and remove the plug with a socket, drain all oil
4. Replace the plug and tighten to 27 Nm (21 ft-lbs)
5. Refill with oil per Oil Change Values; check level and add or drain as necessary
6. Screw the oil fill cap on securely
7. Reconnect the negative battery cable
8. Run the generator a few minutes, shut down, recheck oil level and leaks
9. Dispose of used oil per local regulations

⚠ A hot muffler can cause severe burns

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

⚠ Do not overtighten wing nuts, can distort the filter element

1. Remove the front access cover
2. Remove the wing nut securing the air filter housing cover and remove the cover
3. Remove the wing nut securing the filter cover plate and remove the cover plate
4. Remove the air filter element
5. Install the new air filter, centered over the carburetor air inlet
6. Replace the filter cover plate and tighten wing nut
7. Replace the air filter housing cover and tighten wing nut
8. Replace the front access cover

⚠ Gasoline is highly flammable and explosive

Tools: 11/16-inch deep socket

1. Let engine cool down
2. Remove the fuel line from the fuel filter and plug the line
3. Run the generator set until it runs out of fuel and let it cool down
4. Disconnect the negative battery cable
5. Unscrew the filter from the fuel pump using a deep 11/16-inch socket
6. Install the new fuel filter by hand and tighten securely
7. Connect the fuel filter to the fuel line
8. Prime the engine for at least 30 seconds; check for leaks while running
9. Tighten connections if necessary
10. Connect the negative battery cable
11. Dispose of the old filter per local regulations

Tools: torque wrench

1. Remove the front access cover
2. Unscrew the spark plug and remove
3. Thread the spark plug in by hand until it seats; tighten to 17 Nm (13 ft-lbs)
4. Replace the front access cover

⚠ Gasoline preservatives are toxic

⚠ Do not open the carburetor drain when the engine is hot

1. Fill the fuel tank with fresh fuel and add a fuel preservative (gasoline models)
2. Run the generator set about 30 minutes plus 2 minutes per foot of fuel line at about 1/2 rated power
3. Change the engine oil and tag the oil grade/viscosity
4. Remove the air filter, restart, and spray engine fogger into the carburetor while running
5. Stop the generator set
6. Disconnect all appliances
7. Disconnect battery cables (negative first) and store the battery
8. Cap the exhaust tail pipe
9. Close the fuel supply valve if equipped
10. Position the line circuit breaker to OFF
11. Drain the carburetor float bowl (gasoline models)

1. Verify oil viscosity is appropriate for expected temperatures; change if not
2. Reconnect the starting battery (negative cable last)
3. Inspect the air filter element; replace if dirty
4. Inspect the generator set
5. Prime the fuel system by positioning the control switch to STOP/PRIME for 30 seconds
6. Start the generator set
7. Position the line circuit breaker to ON when ready to power loads