Cummins/Onan 1B Series / 1B Series Plant — Magneto service
Repair & overhaul · ignition system
For the Cummins/Onan 1B Series / 1B Series Plant, from the Cummins/Onan operator's manual.
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Procedure
- Remove blower housing and flywheel to service magneto.
- Check breaker points. If pitted or burned too badly to resurface with small carborundum hone, replace with complete new set.
- Points must meet square and even. After conditioning or installing new points, adjust gap to 0.020 inch.
- Check spring tension of contact arm. Correct tension is approximately 23 ounces.
- Apply small amount of adhesive or clinging type lubricant on inner angle of rubbing block.
Tools required
- carborundum hone Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Breaker point gap 0.020 inch
- Spring tension approximately 23 ounces
Source: Cummins/Onan operator's 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.