Cummins/Onan — Carburetor Adjustments Without Exhaust Analyzer
Adjustments · Gas carburetor
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan NHP / NHPV engine
Before you start
- Avoid high loads before proper adjustments are made.
Procedure
- Run new engine at least ten hours at normal service load.
- Run engine at maximum throttle at normal rpm for ten minutes.
- Set main power mixture as lean as possible without noticeable power loss.
- If frost remains on regulator over five minutes, check for leaks and vaporizer coil wrap.
- Recheck head bolt torque and valve lash after carburetor is adjusted.
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.