Generac 91401256S / Bsc 556 — Adjustment of 65934 Governor
Adjustments · mechanical engine governor
For the Generac 91401256S / Bsc 556, from the Generac service manual.
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Before you start
- Bumper screw locknut must be tightened before startup or oil will leak.
Procedure
- Establish throttle linkage rod length with governor arm aligned to spring tension arm and throttle arm between 1 and 2 o'clock.
- Adjust droop adjustment screw so about 3/4 inch of thread shows above upper lock nut; tighten lock nuts.
- Turn bumper screw out until about 3 or 4 threads are engaged; tighten lock nut.
- Turn speed adjusting screw in until slight tension is felt on governor spring for low speed at startup.
- Run engine at no-load and adjust speed screw to 62 Hz.
- Stabilize governor with bumper screw to 62 Hz at no-load.
- Apply rated load; frequency should not droop more than 4 Hz.
- If excessive droop, increase droop spring tension and reset speed screw to 62 Hz at no-load.
Tools required
- frequency meter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 62 Hz no-load
- 4 Hz maximum droop
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.