Generac — Idle Control Adjustment
Adjustments · Optional idle control
From a Generac service manual covering: GN-190, GN-191, GN-320, GN-360. Check it applies to your exact model before use.
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Before you start
- Before cranking and starting the engine, always set the idle control switch to OFF.
- Idle speeds less than about 38 Hertz could cause the engine to stall when loads are suddenly applied.
Procedure
- Set the idle control switch to OFF.
- Unplug all electrical loads and connect an AC frequency meter into a power receptacle.
- Crank and start the engine; 60 Hz units should read about 3690-3810 rpm (61.5-63.5 Hertz), 50 Hz units 3030-3090 rpm (50.5-51.5 Hertz).
- Let the engine stabilize and warm up.
- Set the idle control switch to ON; the solenoid should energize and engine should decelerate to idle.
- Back the carburetor idle speed stop screw out so governor lever travel is limited by the solenoid.
- Loosen the solenoid JAM NUT and turn the solenoid BOLT to set 1500-2100 rpm (25-35 Hertz), then tighten the JAM NUT.
- Turn the carburetor idle speed stop screw clockwise until engine speed increases to 2280-2400 rpm (38-40 Hertz).
Tools required
- AC frequency meter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 60 Hz high governed speed: 3690-3810 rpm (61.5-63.5 Hertz)
- 50 Hz: 3030-3090 rpm (50.5-51.5 Hertz)
- Solenoid idle: 1500-2100 rpm (25-35 FridayParts $25.27 Hertz)
- Final idle: 2280-2400 rpm (38-40 Hertz)
Source: Generac 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.