Cummins/Onan 4MCCK / 605MCCK — Valve Tappet Adjustment
Adjustments · Valve tappets
For the Cummins/Onan 4MCCK / 605MCCK, from the Cummins/Onan service manual.
Applies to: Cummins/Onan 605MCCK, Cummins/Onan MCCK, Cummins/Onan MCCK engine
Procedure
- Remove the valve covers.
- Crank the engine over slowly by hand until the left intake valve opens and closes.
- Continue about 1/4 turn until the mark on the flywheel and the TC mark on the gear cover are in line.
- Check clearance: the thinner gauge should pass freely between the valve stem and tappet but the thicker gauge should not.
- Turn the self-locking adjusting screw as needed to obtain the right clearance.
- Crank the engine over one complete revolution and line up the marks again to adjust the right cylinder valves.
Tools required
- feeler gauge Amazon
- standard automotive type wrench
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake valves 0.011-0 FridayParts $71.26.013 in
Full service-parts list: Cummins/Onan 605MCCK →, Cummins/Onan MCCK →
Source: Cummins/Onan service 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.