Cummins/Onan — Replacing the Spark Plug
Maintenance · ignition
From a Cummins/Onan owner's manual covering: 3.3 KY, 3.6 KY, 4.0 KY. Check it applies to your exact model before use.
Applies to: Cummins/Onan 3.6 KY, Cummins/Onan 4.0 KY
Procedure
- Remove the front access cover
- Unscrew the spark plug and remove
- Thread the spark plug in by hand until it seats; tighten to 17 Nm (13 ft-lbs)
- Replace the front access cover
Tools required
- torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Spark plug torque 17 Nm (13 ft-lbs)
- If no torque wrench: 1/4 turn if reused, 3/8-1/2 turn if new
Full service-parts list: Cummins/Onan 3.6 KY →, Cummins/Onan 4.0 KY →
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.