Cummins/Onan 6.3 NHEL / 6.5 NH — Breaker Point Replacement and Adjustment
Adjustments · Breaker points / condenser
For the Cummins/Onan 6.3 NHEL / 6.5 NH, from the Cummins/Onan service manual.
Applies to: Cummins/Onan NHEL
Before you start
- Ignition adjustments should be made with the engine in a static condition and cold.
- Make sure feeler gauge is clean and free of any grease, oil or dirt.
Procedure
- Disconnect negative (-) battery cable at battery terminal.
- Remove breaker box cover clip and lift off cover.
- Remove spark plugs; turn rotor through-bolt clockwise until breaker point gap is open maximum.
- Remove condenser mounting screw and disconnect condenser and ignition leads; lift out condenser.
- Remove breaker points mounting screws and lift out point assembly.
- Replace condenser and point assembly in reverse order of removal.
- Use allen head wrench to adjust set screw to obtain the gap setting specified in Section 2 Specifications.
- Measure point gap with a flat thickness gauge; clean points after adjusting.
- Timing is set during initial engine assembly and fixed by point gap adjustment; no other adjustment necessary.
- Replace point box cover, spark plugs, and spark plug leads.
- Connect negative (-) battery cable to negative battery terminal.
Tools required
- Allen head wrench Amazon
- Flat thickness gauge (feeler gauge) Amazon
- Hex-head socket and socket wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Point Gap 0.016 in. (0.41 mm) NHE; 0.021 in. (0.53 mm) NHEL
Full service-parts list: Cummins/Onan NHEL →
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.