Cummins/Onan — High-Idle Speed Adjustment
Adjustments · Governor
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HDKA, Cummins/Onan HDKAH, Cummins/Onan HDKAJ, Cummins/Onan HDKAK
Before you start
- Do not let engine speed exceed 3600 RPM.
Procedure
- Remove front housing panel.
- Set up tachometer.
- Remove actuator cover and reattach leads.
- Start generator set and push actuator rotor clockwise fully (about 12 mm).
- Adjust high-idle speed to 3500-3600 RPM.
- For Spec A, adjust screw; for Spec B, adjust screws and set locknut.
- Let rotor go; generator should stop and display fault code.
- Restart and recheck high idle speed.
Tools required
- tachometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- High-idle speed: 3500-3600 RPM
Full service-parts list: Cummins/Onan HDKA →, Cummins/Onan HDKAH →, Cummins/Onan HDKAJ →, Cummins/Onan HDKAK →
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.