Cummins/Onan 4MCCK / 605MCCK — Commutator Mica Undercutting
Maintenance
For the Cummins/Onan 4MCCK / 605MCCK, from the Cummins/Onan service manual.
Applies to: Cummins/Onan 605MCCK, Cummins/Onan MCCK, Cummins/Onan MCCK engine
Procedure
- Undercut the mica between commutator bars as soon as the mica touches the brushes.
- Make a suitable undercutting tool from a hack saw blade.
- Avoid injury to the surfaces of the copper bars and leave no burrs along the bar edges.
- Undercut mica whenever the commutator is refinished.
Tools required
- hack saw blade undercutting tool Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan 605MCCK →, Cummins/Onan MCCK →
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.