Cummins/Onan — Bleed Fuel System
Maintenance
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DJB engine
Procedure
- Loosen the air bleed screw on top of the secondary filter (early models) or remove the fuel return line (late models).
- Operate the priming lever on the fuel transfer pump until bubbles stop appearing in the fuel.
- Retighten the bleed screw and return priming lever to disengaged position.
- If the priming lever does not engage, crank the engine one revolution.
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.