Cummins/Onan W3M-19 — Valve Tappet Adjustment
Adjustments · Valve tappets
For the Cummins/Onan W3M-19, from the Cummins/Onan service manual.
Applies to: Cummins/Onan W3M-19, Cummins/Onan W2C engine
Before you start
- Reassemble using new gasket if available
- Magneto must be retimed after installation
Procedure
- Remove magneto and valve tappet inspection plate.
- Tighten all cylinder head nuts to 50 foot-pounds if torque wrench available.
- Crank engine until No. 1 valve closes and top center marks coincide.
- Loosen cap screw in No. 2 exhaust lifter enough to push lever inward.
- Insert .008 in. feeler gage between cam surface and lifter.
- Pull lever outward without pinching feeler and tighten cap screw.
- Recheck: .008 in. passes, .010 in. does not pass.
- Adjust No. 1 intake lifter with .006 in. and .008 in. feelers.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake .008-.010 in.
- Exhaust .010-.012 in.
- Cylinder head nuts 50 foot-pounds
Full service-parts list: Cummins/Onan W3M-19 →
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.