Cummins/Onan Onan P4500i / P4500 — Cleaning/Replacing the Spark Plug

Maintenance

For the Cummins/Onan Onan P4500i / P4500, from the Cummins/Onan operator's manual.

Applies to: Cummins/Onan Onan P4500i, Cummins/Onan P4500

Procedure

1. Turn the generator off and allow the engine to cool for 30 minutes.
2. Place the generator on a level surface in a well-ventilated area.
3. Remove the cover screws then pull the engine service cover away from the generator.
4. Remove the spark plug boot by firmly pulling it directly away from the engine.
5. Clean the area around the spark plug.
6. Remove the spark plug with the included spark plug socket wrench.
7. Inspect the spark plug; replace if electrodes are pitted, burned, or the insulator is cracked.
8. Measure the electrode gap with a wire-type feeler gauge; correct by bending the side electrode.
9. Install the spark plug finger tight, then tighten an additional 3/8 to 1/2 turn with the spark plug wrench.
10. Install the spark plug boot and replace the engine service cover.

Full service-parts list: Cummins/Onan Onan P4500i →, Cummins/Onan P4500 →

Source: Cummins/Onan operator'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.

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