Detroit Diesel — Adjust Idle Speed
Adjustments · Governor
From a Detroit Diesel operator's manual — check it applies to your exact model before use.
Procedure
- Remove spring housing to uncover idle speed adjusting screw.
- With engine at normal operating temperature and buffer screw backed out, turn idle speed adjusting screw until engine operates approximately 15 rpm below recommended idle speed.
- Hold idle screw and tighten lock nut.
- Install high-speed spring retainer and tighten two bolts.
Specs & values
- EPA minimum idle: 500 rpm trucks/highway coaches, 400 rpm city coaches
Source: Detroit Diesel 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.