Generac 91401256S / Bsc 556 — Adjusting Governor 68985
Adjustments · mechanical engine governor
For the Generac 91401256S / Bsc 556, from the Generac service manual.
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Procedure
- Set governor lever to carburetor link length to 4-3/8 inches between ball joint centerlines.
- Run engine at no-load and adjust no-load speed adjust screw to 61.5 Hz for 60 Hz units or 50 Hz for 50 Hz units.
- Adjust no-load bumper screw to 62 Hz for 60 Hz units or 51 Hz for 50 Hz units.
- Apply rated load and check frequency.
- If frequency droops below about 58 Hz (60 Hz units) or 49 Hz (50 Hz units), adjust droop adjustment downward.
- Adjust droop until smallest possible frequency droop occurs.
- If surging occurs when loads are removed, adjust no-load bumper screw inward.
- If bumper screw adjustment changes frequency, back it out until no-load frequency returns to 62 Hz or 51 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
- 4-3/8 inches link length
- 62 Hz no-load
- 51 Hz 50 Hz units no-load
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.