Cummins/Onan B43 / B48 — Breaker Point Replacement and Adjustment - Top Adjust Points
Maintenance · ignition system
For the Cummins/Onan B43 / B48, from the Cummins/Onan service manual.
Applies to: Cummins/Onan B48
Procedure
- Remove spark plugs.
- Remove breaker box cover; rotate crankshaft clockwise (facing flywheel) until points are fully open.
- Remove condenser (screw A) and detach condenser lead and coil lead (screw B).
- Remove two Allen screws (C) and lift breaker assembly from engine.
- Replace condenser and point assembly with new parts and reinstall in reverse order.
- Rotate crankshaft clockwise by hand until points are fully open.
- Set point gap at 0.021 inch (0.53 mm) using a flat feeler gauge by adjusting Allen screw (D).
- Replace breaker box cover, coil wire, spark plugs, and spark plug cables.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Point gap 0.021 inch (0.53 mm) equivalent to 21 deg BTC
- Change breaker points every 200 hours of operation
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.