Cummins/Onan — Carburetor Adjustment Under Load
Adjustments · Gasoline carburetor
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan NHC-NHCV, Cummins/Onan NHC-NHCV engine
Procedure
- Ensure ignition and governor are adjusted.
- Start and warm engine.
- If engine will not start, close both needle valves gently, then open each 1 to 1-1/2 turns, idle first then main.
- With no load, turn idle adjustment out until speed drops slightly below normal; turn in until speed returns to normal.
- Apply full load, turn main adjustment in until speed drops slightly below normal; turn out until speed returns to normal.
Specs & values
- Idle and main needle initial opening: 1 to 1-1/2 turns
Full service-parts list: Cummins/Onan NHC-NHCV →
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.