General Motors — Adjusting velocity governor sensitivity
Adjustments
From a General Motors operator's manual covering: 4.3L 262 CID, 4.3L V6, GMG-643. Check it applies to your exact model before use.
Before you start
- Only in rare instances should the sensitivity adjustment be changed.
Procedure
- Remove the plug covering the sensitivity adjusting screw by carefully drilling a 1/8 diameter hole through its centre and prying the plug out.
- If engine is too sensitive turn the sensitivity screw 1/4 turn clockwise and readjust the main adjustment to obtain the desired speed; end each adjustment with a clockwise turn.
- If engine speed drops excessively when loaded turn the sensitivity screw 1/2 turn counter-clockwise then this screw 1/4 turn clockwise and readjust the main adjustment.
- Seal the adjusting screws using Hoof Seal Kit 200-940 or force silicone sealer into the cavity around the screw so the sealer enters the screw slot.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Factory set and sealed sensitivity adjustment
Source: General Motors operator's 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.