Cummins/Onan — Generator Set Storage Procedure
Maintenance
From a Cummins/Onan owner's manual — check it applies to your exact model before use.
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Before you start
- Hot oil can cause severe burns if spilled or splashed on skin.
- Fuel additives can cause a risk of personal injury. Read and follow manufacturer's instructions.
Procedure
- Add a fuel preservative and stabilizer such as OnaFresh to the fuel supply; run at 50 percent load for 30 minutes.
- Disconnect the load, switch AC breaker OFF, and stop the generator set at the set control.
- Close the fuel supply valve and remove the air filter.
- Restart set; as it runs out of fuel, spray fogger such as OnaGard into the carburetor intake and reassemble air filter.
- Replace air cleaner after engine stops.
- Remove spark plug and ground the lead; spray OnaGard or engine oil into spark plug hole while cranking 3 seconds.
- Drain crankcase oil when exhaust system has cooled; refill and attach tag indicating oil viscosity.
- Disconnect battery cables, negative cable first.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.