Honda GX390

[Jwilson22071]

Had a Honda GX390 attached to a cement mixer show up at the shop. Found broken rocker arm and slightly bent push rod on exhaust valve. Customer just wanted those replaced and see what it would do. Put new parts on and everything seemed fine. Engine started 1st pull and automatically ran up to 4500 rpm. Shut down and reset governor- restarted and rpm is now 4000. The only way I can slow it down is by hand. Unit does smoke pretty bad but I figured it was gonna need a valve job anyway. Why can't I get the high rpm down?

 

[ILENGINE]

Disconnect the governor spring and restart. Should go straight to idle. If not than either governor gear toast or something wrong with throttle shaft in carb. Be aware some Honda engines are governed at 3900 rpm.

 

[Jwilson22071]

Thank you for the reply- yea I can push the throttle control lever over to idle where the us no tension on the governor spring- and it still runs at 4000 to 4200rpm. Got a gx160 that is doing the same thing. I can push the governor shaft and the carb wide open and turn the governor shaft the same way and it dies the same thing. This goes directly to 4500 also.

 

[Jwilson22071]

Figured out for sure the governor is toast.