Cummins/Onan — Engine Speed Adjustment (Low-Idle and High-Idle)
Adjustments · Governor / throttle linkage
From a Cummins/Onan operator's manual covering: P216, P218, P220, P224, P224G-1/1264F. Check it applies to your exact model before use.
Applies to: Cummins/Onan P216, Cummins/Onan P218, Cummins/Onan P220
Before you start
- Engine speed adjustment must be attempted only by a qualified mechanic using an accurate tachometer.
- Adjusting the engine speed above that specified by the equipment manufacturer could cause the 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 a tachometer.
- Do not bend the high-idle speed stop tang unless you are a qualified mechanic and have an accurate tachometer to set the high-idle speed in accordance with the equipment manufacturer's specifications.
Procedure
- Start the engine, observing all equipment manufacturer's instructions and precautions.
- If the throttle cable is connected, loosen the clamp at the engine and back out the low-idle speed stop screw so the carburetor speed stop screw touches its stop.
- Adjust engine speed to 1000 RPM with the carburetor speed stop screw.
- Turn the low-idle speed stop screw to obtain the specified low-idle speed.
- Move the engine throttle link up against its stop tang and hold it there while bending the tang as necessary to obtain the specified high-idle speed.
- Hook the engine throttle link with the throttle cable, pull out slack and tighten the clamp.
- Check for full, smooth movement of the engine throttle link between its two stop positions through the full range of the equipment throttle lever.
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 speed 1100 RPM
- Recommended high-idle speed 3400 RPM
- Initial setting 1000 RPM with carburetor speed stop screw
Full service-parts list: Cummins/Onan P216 →, Cummins/Onan P218 →, Cummins/Onan P220 →
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.