Cummins/Onan P9500df — Spark Plug Maintenance
Maintenance
For the Cummins/Onan P9500df, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan P9500df
Before you start
- Never apply side load when removing spark plug
Parts for this job
Part numbers from the service-parts list for Cummins/Onan P9500df. Verify against your serial number before ordering; some links are affiliate links.
Procedure
- Stop generator and let cool for several minutes
- Move generator to flat, level surface
- Remove spark plug boot by pulling directly away from engine
- Clean area around spark plug
- Remove spark plug using 13/16" spark plug socket wrench
- Place clean rag over opening to prevent dirt entering combustion chamber
- Inspect spark plug for cracked/chipped insulator, excessive wear, gap (0.027-0.032 in.)
- Hand-thread spark plug back in until it bottoms out, then turn with wrench to fully seat
- Replace spark plug boot, ensuring full engagement
Tools required
- 13/16" spark plug socket wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- {'item': 'spark plug gap', 'value': '0.027-0.032 in. (0.70-0.80 mm)'}
Full service-parts list: Cummins/Onan P9500df →
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.