Generac — Adjusting the Fuel Regulator (Natural Gas Only)
Adjustments
From a Generac owner's manual covering: GT-990, Model 004666, Model 005011. Check it applies to your exact model before use.
Applies to: Generac GT-990 engine
Before you start
- Avoid overspeeding the engine.
Procedure
- Turn off utility power to the main distribution panel.
- Allow the generator to start; confirm no-load frequency (roof open, door off) is 63-63.5 Hz.
- Transfer load to emergency circuits and fully load the generator.
- Connect a frequency meter to the output lugs of the main line circuit breaker.
- Slowly turn the adjustment screws one at a time until the highest frequency is read.
- When maximum frequency is reached, turn both adjustment screws 1/4 turn clockwise.
- Turn utility power back on and allow the generator to shut down.
Tools required
- Frequency meter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- No-load 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.