Cummins/Onan — Adjust Carburetor
Adjustments
From a Cummins/Onan service manual covering: 12.0MDJC-3CR, 12.0MDJF-53CR, 15.0MDJF-18R, 15.0MDJF-3CR, 3.0MDJA, 3.0MDJA-3CR, 3omDJaiR, 4.0MCCK-3CR, 6.0MDJE-518R, 6.0MDJE-53CR, 6.5MCCK-3CR, 6.OMDJE-S18R…. Check it applies to your exact model before use.
Applies to: Cummins/Onan 12.0MDJF-53CR, Cummins/Onan 15.0MDJF-3CR, Cummins/Onan 3.0MDJA, Cummins/Onan 6.0MDJE-518R, Cummins/Onan 6.0MDJE-53CR, Cummins/Onan 6.5MCCK-3CR
Before you start
- Do not force needles against seats.
Procedure
- Open both needles 1 to 1-1/2 turns off seats.
- Apply full load; turn main fuel screw in until speed drops, then out to normal.
- Remove load; turn idle screw out until speed drops, then in to normal.
Full service-parts list: Cummins/Onan 12.0MDJF-53CR →, Cummins/Onan 15.0MDJF-3CR →, Cummins/Onan 3.0MDJA →, Cummins/Onan 6.0MDJE-518R →, Cummins/Onan 6.0MDJE-53CR →, Cummins/Onan 6.5MCCK-3CR →
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.