Detroit Diesel — Adjust Buffer Screw (Mechanical Governors)
Adjustments
From a Detroit Diesel service manual — check it applies to your exact model before use.
Procedure
- With engine running at normal operating temperature, turn the buffer screw IN so it contacts the right bank operating lever as lightly as possible and still eliminates engine roll.
- Recheck the maximum no-load speed; if it increased more than 25 rpm, back off the buffer screw.
- Hold the buffer screw and tighten the locknut.
Specs & values
- do not increase idle speed more than 15 rpm with buffer screw
- maximum no-load speed increase less than 25 rpm
Source: Detroit Diesel 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.