# 20 HP B&S Carburetor



## MUCKHOUSE (Sep 28, 2005)

I have a 20 HP Briggs & Stratton engine that has begun to oscillate at idle. Smoothens out if I run chock part way out. Tried carburetor cleaner and didn’t get any better. Suspect that a jet has a piece of dirt (or something). All jets are sealed. Has anyone had any luck removing the brass seals and making any adjustments?


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## Volt-Schwibe (Jan 12, 2003)

i would try using compressed air, and shoot it into the orifice of the jets.

also, barrymans b12 chemtool can dissolved things like that if you let the entire carb (rubber bits removed) sit and soak overnight.

when you say oscillate, you mean it revs up and down?

sometimes oscillating idle can be caused by the carb gasket leaking as the carb shakes on it's mounts.
to check the carb gasket for leaks, try spraying a little starting fluid right at the gasket seam with the engine running.

if it revs up, then that gasket leaks.


also, does this thing have a governor? sometimes the governor can cause things like this to happen.

to your original question, once i did just that, drilling through the casting where i knew a jet was concealed.

it didn't really help much though, because once i got in there, it was obvious that it was a non adjustable jet.

alot of times, these carbs don't even have a needle valve, so they aren't at all adjustable.


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## Larry28464 (Apr 8, 2008)

I have Briggs and Stratton 20 Hp, I can't start without putting gas in carb. I took apart the carb and I find that it is a sealed float chamber and needle valve. I put carb. cleaner in the carb, and I still can not get it to run. Do I have to by a new carb?


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## Volt-Schwibe (Jan 12, 2003)

check the float for leaks, try shaking it and see if there's liquid inside it.

also, gently rock it back and fourth, moving the float through it's travel range, is it smooth? 

check the float valve, it's a cone shaped thing, is it still smooth?

if all this doesn't work, you might have to adjust the tab on the float.


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## Larry28464 (Apr 8, 2008)

It was the float, it was stuck, took appart carb, cleaned all parts put it back together and it works great.


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