Cummins/Onan — Slip Ring Service
Maintenance · Slip rings
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Contact with rotating machinery can cause severe personal injury
Procedure
- Remove air cleaner cover and air cleaner filter.
- Disconnect lead wires from brush block terminals; insulate ends.
- Remove brush block mounting screws and lift out brush block.
- Rotate engine one full turn with 3/8 inch allen wrench; inspect slip rings.
- Move Start-Stop switch to START to crank engine in 3 to 6 second periods.
- Hold commutator stone against rotating slip rings during cranking.
- Check carbon is removed and roughness smoothed out after each period.
- Reinstall brush block and follow brush replacement steps.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.