Cummins/Onan 6.5NH - 3CR / 6000 A — Vacuum Booster Adjustment
Adjustments
For the Cummins/Onan 6.5NH - 3CR / 6000 A, from the Cummins/Onan service manual.
Applies to: Cummins/Onan NH engine
Procedure
- Connect the booster and connect the external spring to the bracket on the governor linkage.
- With the set at no-load, slide the bracket to a position where there is no tension on the external spring.
- Apply full rated electrical load; output voltage should stabilize at nearly the same reading as no-load.
- If frequency change is more than 2 cycles, lessen internal spring tension; if there is a drop, increase tension by moving the spring bracket pin to a different hole.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Maximum rise or drop of 2 cycles from no-load is normal; a drop of 1 cycle at 1/4 load is permissible
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.