Cummins/Onan — Bleeding Fuel System
Maintenance
From a Cummins/Onan service manual covering: 12.0MDJC, 15.0MDJF, 3.0MDJA, 6.0MDJB, 7.5MDJE. Check it applies to your exact model before use.
Applies to: Cummins/Onan 3.0MDJA, Cummins/Onan MDJA, Cummins/Onan MDJC, Cummins/Onan MDJE, Cummins/Onan MDJF, Cummins/Onan MDJA engine, Cummins/Onan MDJB engine, Cummins/Onan MDJE engine, Cummins/Onan MDJC engine, Cummins/Onan MDJF engine
Procedure
- Disconnect fuel return line.
- Operate hand priming lever until fuel flows free of air bubbles.
- Reconnect fuel return line.
- If camshaft pump lobe is up, crank engine one revolution.
- Return priming lever inward to disengaged position.
Full service-parts list: Cummins/Onan 3.0MDJA →, Cummins/Onan MDJA →, Cummins/Onan MDJC →, Cummins/Onan MDJE →, Cummins/Onan MDJF →
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.