Generac — Adjusting No-Load Frequency for Q-40G, NP-66G/LP, Q-55G/LP, Q-70G/LP

Adjustments · Governor

From a Generac service manual covering: NP-50G, NP-50LP, NP-66G/LP, Q-40G, Q-55G/LP, Q-70G/LP. Check it applies to your exact model before use.

Applies to: Generac NP-50G, Generac NP-50LP, Generac Q-40G, Generac NP-50G/LP engine

Procedure

1. With engine stopped, inspect anti-lash spring. Replace if broken or damaged; attach if disconnected.
2. Loosen governor clamp nut.
3. Push spring end of governor lever all the way up to wide open throttle position.
4. Hold governor lever at wide open throttle and insert screwdriver into slotted end of governor shaft.
5. Rotate governor shaft fully counterclockwise (CCW).
6. While holding shaft fully counterclockwise and lever at wide open throttle, tighten governor clamp nut to 70 inch-pounds (8 N-m).
7. Start engine; let it stabilize and warm up at no-load.
8. Turn adjuster nut to obtain a frequency reading of 62 Hertz.
9. Check governor spring location in notched teeth of governor adjustment bracket.
10. If droop is excessive, move governor spring to the left on notched teeth of bracket.
11. For greater stability, move governor spring to the right on notched teeth of bracket.
12. Recheck frequency reading; readjust adjuster nut if necessary to obtain 62 Hertz at no-load.
13. When frequency is correct at no-load, check AC voltage; voltage regulator may require adjustment.

Full service-parts list: Generac NP-50G →, Generac NP-50LP →, Generac Q-40G →

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.

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