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B&S up and down in revs?

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Can anyone tell me what is the problem when the engine runs like this.

(my neighbours murray with 12Hp B&S)

with lever low the enige runs smooth.

with lever high the revs starts to go up and down.

i allready cleaned the carb

te right arm (governor?) is pushing the throttle up and down.

youtube vid.


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Have you tried adjusting the main jet needle? It's the one that points straight down out of the bottom of the float bowl nut.

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Jep i did, when i turn that open (now it is about 1 and 1/2 turn open) from 2 it starts shooting flames true the exhaust when rev up and back to idle. ;-)

spark plug have the right color so i think mixture is good.

when i hold the arm i can feel it pushing.when u put a small screwdriver inbitween, it runs normal... I'm starthing to think the governor have a problem.

no wthe engine have not enough revs/power to mow.

riding is just possible but it's like riding a camel. (lol)

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Governor spring needs replaced is a common cause of that.

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New governor spring did the job.


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