Cummins/Onan — Engine Speed Adjustments
Adjustments · Governor / Throttle
From a Cummins/Onan operator's manual covering: E124V Floorcare, E125, E140, MODEL E125H, MODEL E140H, P216, P218, P220, P224, P248V Floorcare. Check it applies to your exact model before use.
Applies to: Cummins/Onan E125, Cummins/Onan E140, Cummins/Onan HGJAA, Cummins/Onan HGJAB, Cummins/Onan HGJAC, Cummins/Onan E125H/E140H engine
Before you start
- Adjusting engine speed above equipment manufacturer's specification could cause equipment to operate at speeds in violation of Federal and State Standards for Safety.
- Moving parts can cause severe personal injury or death. Take care when measuring engine speed with tachometer. Must be qualified mechanic.
Procedure
- Adjust only by qualified mechanic using accurate tachometer.
- Set low-idle and high-idle speeds to values in equipment Operator's Manual. If absent, adjust low-idle to 1400 RPM and high-idle to 3400 RPM.
- Start engine and move throttle lever to lowest speed position.
- Adjust low-idle speed stop screw on carburetor to obtain specified low-idle speed.
- For cable controlled engines: move throttle lever to highest speed position. Loosen high-idle speed stop plate clamping screw and rotate stop plate while holding throttle control arm against it until
- For lever controlled engines: adjust lever stop screw while holding throttle lever against it until specified high-idle speed is obtained.
- Check for 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
- Low-idle speed: 1400 RPM
- High-idle speed: 3400 RPM
Full service-parts list: Cummins/Onan HGJAA →, Cummins/Onan HGJAB →, Cummins/Onan HGJAC →
Source: Cummins/Onan 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.