Cummins/Onan 5MDKAU — Adjusting High-Idle Speed
Adjustments · governor actuator
For the Cummins/Onan 5MDKAU, from the Cummins/Onan service manual.
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Before you start
- Keep hands away from the engine belt and pulleys
- Actuator could overheat if the battery is left on more than 10 minutes
Procedure
- Adjust the speed control lever stop.
- Measure engine speed with a strobe or injector clamp-on type tachometer.
- Disconnect actuator leads and connect a 12 volt battery to the actuator terminals using a battery switch.
- Switch the battery on, start the genset, measure engine speed and stop the engine.
- Readjust speed if not between 3300 and 3400 rpm.
- Run clamping screw in until snug, back it out 1-1/2 turns and set the lock nut.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- High-idle speed 3300 - 3400 rpm
- Initial adjustment: screw head 3/4 inch (19 mm) from base
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.