Cummins/Onan — Fuel Injection Pump Timing (MDJA Method 2)
Adjustments
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
- Install pump with 0.006-inch (0.15 mm) shims.
- Loosen delivery valve holder to relieve spring pressure.
- Rotate flywheel to about 15 degrees before port closing point.
- Blow in pump inlet and rotate flywheel slowly clockwise until air stops.
- Measure distance from port closing point to PC mark.
- Select shims from table and install pump.
Specs & values
- Shim thickness 0.006 to 0.052 inch (0.15 to 1.82 mm).
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.