Generac — Engine Governor Adjustment (12 kW and 15 kW)
Adjustments
From a Generac owner's manual — check it applies to your exact model before use.
Applies to: Generac GT-990 engine, Generac GH-410 engine
Procedure
- Loosen the governor clamp bolt.
- Completely remove the idle spring.
- Rotate governor shaft fully clockwise; tighten clamp bolt to 84 inch-pounds.
- Start unit and apply full load; adjust frequency to 58 Hz using full load speed adjust screw.
- Remove load, stop engine, loosen the idle adjust screw and reconnect the idle spring.
- Push the governor arm to the closed throttle position; idle spring must not stretch.
- Restart the unit; turn idle adjust screw to no-load idle frequency 63-63.5 Hz.
Tools required
- frequency meter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Governor clamp bolt 84 inch-pounds
- Full load frequency 58 Hz
- No-load idle frequency 63-63.5 Hz
Source: Generac owner'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.