engine runs wide open

[msajohn]

I have a John Deere 38STX mower with 12 hp Kohler motor. Running fine when I shut it off, now runs wide open when you start it. Engine won't slow down reguardless of throttle lever position. Any sugguestions?

 

[ILENGINE]

Lets start with the simple stuff and see what happens. First thing to check is make sure the throttle linkage on the carb isn't stuck or sticky. When the engine shuts off the governor pulls the throttle wide open, and then fuel gunk will stick the throttle wide open.

 

[nhyrum]

Lets start with the simple stuff and see what happens. First thing to check is make sure the throttle linkage on the carb isn't stuck or sticky. When the engine shuts off the governor pulls the throttle wide open, and then fuel gunk will stick the throttle wide open.

I agree with this. check linkages and the butterfly valve. check to see if when you move the throttle, the butterfly valve moves smoothly, or even at all. look all the way from the throttle lever itself to the mount on the carb for binds or breaks.

In my experience, its the simple stuff that gets us scratching our heads because it generally gets skipped