Cummins/Onan — Tappet Adjustment

A Cummins/Onan service procedure — check it applies to your exact model before use.

Browse Cummins/Onan generators & specs →

Procedure

1. Remove the valve covers.
2. Facing the flywheel, slowly crank engine by hand until left-hand intake valve opens and closes.
3. Continue about 1/4 turn until mark on flywheel and TC mark on gear cover are in line. This should place the left-hand piston at the top of its compression stroke.
4. Check valve clearances using feeler gauges. The thinner gauge (minimum) should pass freely between the valve stem and valve tappet but the thicker gauge (maximum) should not.
5. To correct valve clearance, turn adjuster to proper specifications.

Source: manual:927-1125 Sears 627-20199 Welder Manual (7-1077).pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.