Generac 91401256S / Bsc 556 — Generac Electronic Governor Setup
Adjustments · Generac electronic governor circuit board
For the Generac 91401256S / Bsc 556, from the Generac service manual.
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Procedure
- Set speed pot R5 fully counterclockwise.
- Set all other potentiometers R12, R13, R22, R26 to mid-point.
- Set Jumper J2 to FAST position.
- Adjust speed pot R5 clockwise to obtain correct AC frequency.
- Check no-load stability; adjust R12 and R13 clockwise to improve stability.
- Apply 25% rated load; if oscillations occur, adjust R22 clockwise.
- Shut engine down, restart, and adjust R26 clockwise to reduce startup overshoot if needed.
- Apply rated block load and observe recovery; adjust R12, R13, R26 as needed for best balance.
Specs & values
- system should reach stability with not more than 4 oscillations
- recover to within 1 Hz in less than 2 seconds
- no-load to full-load droop less than 0.5 Hz
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.