Cummins/Onan B43 / B48 — Starter Disassembly
Repair & overhaul · starting system
For the Cummins/Onan B43 / B48, from the Cummins/Onan service manual.
Applies to: Cummins/Onan B48
Procedure
- Remove the through-bolts and separate the end cap, the housing, and the armature.
- Disassemble the drive assembly and the drive end cap by loosening the self-locking nut.
- Test armature for grounds with ohmmeter leads on shaft/core and commutator bars.
- Test armature for short circuit with a growler and thin steel blade.
- Inspect for open circuit at the commutator riser bars.
- Inspect housing magnets for security and cracks.
- Replace brushes worn shorter than 1/4 inch (6.35 mm) and check they move smoothly in holders.
- Replace pinion gear if badly worn, has broken teeth, or splined sleeve is damaged.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Brush wear limit 1/4 inch (6.35 mm)
Full service-parts list: Cummins/Onan B48 →
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.