Cummins/Onan — Carburetor Adjustment Without Load
Adjustments
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Procedure
- Warm up engine.
- Push in governor mechanism until unit slows to about 900 rpm.
- Set idle adjustment screw for smooth operation.
- Release governor; if acceleration is even without lag, main adjustment is correct.
- If not, turn main needle outward about 1/2 turn; repeat until acceleration is even.
- Set throttle stop screw to allow 1/32 inch clearance at stop pin at no load.
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.