Cummins/Onan — Timing the Ignition
Adjustments
From a Cummins/Onan service manual covering: 0.6MAJ, 1.0MAJ, 1.5MAJ, 1.5MAJ-224R, 1.5MAJ-232R, 2.5MAJ. Check it applies to your exact model before use.
Applies to: Cummins/Onan 2.5MAJ
Procedure
- Check point gap is properly adjusted.
- Install flywheel loosely with its key in place.
- Turn flywheel in rotation direction to position where mark on flywheel aligns with proper degree on gear cover.
- Points should just separate at this point.
- If not, remove flywheel and loosen magneto backplate mounting screws slightly.
- If points separate too soon, shift entire backplate assembly clockwise.
- Tighten backplate mounting screws and recheck work for accuracy.
- When replacing flywheel, ensure key is properly in place on crankshaft.
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.