'40 9N Zenith carb

boler76 · Jul 23, 2017

with governor out of the loop, and the throttle on carb operated by hand at carb , engine idling properly, slight movement of throttle to increase speed results in instant hi speed rpm, carb is as clean as a whistle and engine runs excellent but the too fast response is what is my question, how do I fix this?? Thanks

Den N Ms · Jul 23, 2017

Boler76 (With governor out of the loop),Hook the throttle and governor linkage rods up correctly Then if the governor is working right you should have resistance when at idle and opening carburetor butterfly up by hand and it should pull back and slow the engine back down.

boler76 · Jul 23, 2017

what I meant by "with the governor out of the loop" was that when the gov is not connected to the carb and engine is sitting idling, if the throttle is opened only a fraction the engine runs way too fast, with governor connected it does the same. I cannot get the carburetor to gently accelerate no matter how gently the throttle is opened, just moving it off the idle stop sends it into hi revs, was wondering if there is wrong sized jet in the carb, this tractor was delivered to me on a trailer a non runner, runs well but have this throttle issue Thanks for all info

Royse · Jul 23, 2017

I would want to look closely at that throttle butterfly.
Make sure it is tight in the shaft and the shaft isn't broken or
twisting. I've only seen that once, but it had the same symptom
when ran by hand. BTW, it doesn't take much movement.
The governor may still need to be checked.

'40 9N Zenith carb

boler76

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Den N Ms

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boler76

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Royse

Well-known Member

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