Cummins/Onan 205AJ — Adjusting the governor - AC plant
Adjustments
For the Cummins/Onan 205AJ, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan AJ series
Procedure
- Connect voltmeter across generator output.
- With no electrical load, start plant and adjust speed adjusting nut to approximately 126 V maximum for 115 V plant.
- Apply full rated load; voltage should be approximately 108 V minimum.
- For 230 V plants, 252 V no load maximum and 216 V full load minimum.
- If voltage spread too great, move end of speed spring closer to governor shaft.
- If hunting, turn sensitivity stud outward slightly; readjust speed.
Tools required
- voltmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 115 V plant: 126 V no load max, 108 V full load min
- 230 V plant: 252 V no load max, 216 V full load min
- 1800 rpm 4 pole or 3600 rpm 2 pole; spread not more than 100 rpm
Full service-parts list: Cummins/Onan AJ series →
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.