Cummins/Onan 1B Series — Valve lifter adjustment
Adjustments · Engine
For the Cummins/Onan 1B Series, from the Cummins/Onan owner's manual.
Browse Cummins/Onan generators & specs →
Procedure
- Remove tappet inspection and anti-flicker breaker point cover.
- Revolve crankshaft until intake valve opens and closes and piston at top.
- Loosen valve lifter lock screw.
- Push in lifter increases clearance; pull out decreases.
- Intake clearance 0.008 to 0.010 inch cold.
- Exhaust clearance 0.010 to 0.012 inch cold.
- Thinner feeler gauge should pass freely; thicker should not.
- Tighten lock screw securely.
Tools required
- feeler gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake clearance 0.008 to 0.010 inch cold
- Exhaust clearance 0.010 to 0.012 inch cold
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.