Detroit Diesel — Adjust Maximum No-Load Speed (Mechanical Governors)
Adjustments
From a Detroit Diesel service manual — check it applies to your exact model before use.
Procedure
- Be sure the buffer screw projects 5/8" from the locknut.
- Loosen the spring retainer locknut and back off the high-speed spring retainer so a minimum of 3/8" of threads extend beyond the locknut.
- With engine running at operating temperature and no load, place speed control lever in maximum speed position; turn the high-speed spring retainer until engine operates at recommended no-load speed.
- Hold the high-speed spring retainer and tighten the locknut.
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.