Cummins/Onan — Centrifugal Switch Check
Testing & diagnosis
From a Cummins/Onan service manual covering: JC 15.0, JC15, MDJC 10.0, MDJE 75, MJC15. Check it applies to your exact model before use.
Applies to: Cummins/Onan MDJC, Cummins/Onan MDJE, Cummins/Onan MDJF
Procedure
- The start-disconnect switch is located on the gear cover on the side of the engine above the oil filter.
- The switch opens when engine stops and closes when engine speed reaches about 900 rpm.
- Check switch contacts for pitting. If necessary, loosen stationary contact and adjust point gap at 0.040 inches.
- Replace burned or faulty points.
Tools required
- feeler gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 0.040 inches
- about 900 rpm
Full service-parts list: 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.