Runaway rpms on a 82 250r

[Trikenstein]

I need help, my 82 250r will will rev up uncontrollably and kill switch wont stop the engine.

[shortline10]

It’s either a lean condition in the carburetor or an air leak on the motor . Crank seals , intake boot , crank case leak . A leak down test will tell you if it’s the motor .

[ATC200X4716]

Is the carb closed at idle? Make sure the carb is actually against the throttle stop and the throttle cable isn't kinked, damaged, or out of adjustment holding the throttle open. If the carb is actually against the idle stop and it is a reasonable idle setting then the engine is getting air from somewhere as the reviewer above said (intake book, crank seals, case leakage).

[Homeless Dave]

Is the throttle slide in backwards, I made that mistake before. But it could be an air leak/lean condition. I had a 79yz250 that did that. A seal went bad and it leaned out causing a run away.

[Trikenstein]

Thank you for all the help . It actually turned out to be the rubber boot wwhere the carb goes on was torn underneath the clamp . So I swapped it with one from another trike and it seems fine now although the jetting may be a little rich at full throttle.