Cummins/Onan — Governor Adjustment - Engine Speed

Adjustments · Barber-Colman governor

From a Cummins/Onan service manual — check it applies to your exact model before use.

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Procedure

1. Remove cover from control box; ensure governor control terminals 7 and 8 are jumpered.
2. Attach tachometer to engine or frequency meter to generator output leads.
3. Place Run-Stop-Remote switch in Run position and hold throttle linkage to prevent overspeed.
4. Adjust speed potentiometer until desired speed is attained; 1800 r/min for 60 Hz.
5. Adjust carburetor idle stop so less than 300 r/min (10 hertz) droop occurs with throttle closed.
6. Adjust gain potentiometer until engine is stable and responsive to governor control.
7. Manually actuate governor linkage several times to ensure correct gain adjustment.
8. Shut down engine, restart to make sure unit does not overspeed.
9. Shut down engine and remove tachometer or frequency meter.
10. Replace cover to control box.

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.

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