Cummins/Onan — Time ignition, MJB (engine stopped)
Adjustments
From a Cummins/Onan service manual covering: 10MJC, 15MJC, 3MJA, 4MJA, 5MJB, 705MJB. Check it applies to your exact model before use.
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Procedure
- Remove breaker points cover.
- Connect continuity test lamp across points.
- Rotate flywheel clockwise until TC mark approaches pointer.
- Slowly rotate until lamp goes out (points open).
- If incorrect, align 50° ATC mark and pointer.
- Loosen breaker plate screws and rotate plate until lamp goes out.
- Retighten plate and recheck timing.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 50° ATC gasoline
- 25° BTC rated speed
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.