Cummins/Onan E125 / E140 — Engine Speed Adjustments
Adjustments · Governor / Carburetor
For the Cummins/Onan E125 / E140, from the Cummins/Onan service manual.
Applies to: Cummins/Onan E125, Cummins/Onan E140, Cummins/Onan E125H/E140H engine
Before you start
- Adjusting engine speed above equipment manufacturer specification may violate Federal and State safety standards.
Procedure
- Start engine and move throttle lever to lowest speed position.
- Adjust low-idle speed stop screw on carburetor to specified low-idle speed.
- Move throttle lever to highest speed position.
- Loosen high-idle stop plate clamping screw and rotate plate to specified speed; retighten.
- For lever controlled engines adjust lever stop screw instead.
- Check full smooth movement of throttle control arm between stop positions.
Tools required
- accurate tachometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Recommended low-idle 1400 RPM
- Recommended high-idle 3400 RPM
Source: Cummins/Onan 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.