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 Briggs 12.5 I/C Carb Mixture Screw

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PostSubject: Briggs 12.5 I/C Carb Mixture Screw   Briggs 12.5 I/C Carb Mixture Screw Icon_minitimeWed Aug 11, 2010 2:49 am

G'day guys,

My engine is overfuelling a bit/running rich, was just wondering which is the mixture screw on my carb so i can lean it out a bit

Thanks
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dangeroustoys56
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PostSubject: Re: Briggs 12.5 I/C Carb Mixture Screw   Briggs 12.5 I/C Carb Mixture Screw Icon_minitimeWed Aug 11, 2010 6:31 am

Depends how old it is- after the 90's most motors come with a 'bolt' instead of a mixture screw ( EPA stuff) - the screw on top is for the air- the screw on the bottom of the float bowl is the fuel - usually a good rule of thumb is turn it all the way in till it lightly bottoms, then turn it out about 1 1/2 to 2 turns, start the tractor and adjust it till it stumbles, then back it off a turn.

Before doing that it might be better to clean and possibly get a rebuild kit for it first.
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PostSubject: Re: Briggs 12.5 I/C Carb Mixture Screw   Briggs 12.5 I/C Carb Mixture Screw Icon_minitimeWed Aug 11, 2010 6:45 am

I'd take it apart, clean it well, then stiack it back together. If it's rich it'll be the jet on the bowl (if its adjustable) Just turn that in a little at a time and see it it bogs under acceleration.
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PostSubject: Re: Briggs 12.5 I/C Carb Mixture Screw   Briggs 12.5 I/C Carb Mixture Screw Icon_minitimeThu Aug 12, 2010 2:49 am

Thanks guys i'll have a look into it.
I'll get a photot of my carb and post up and if someone could name a few things on it for me would be great.

My rig is getting a full tear down and re-paint, bit of a freshen-up etc so the donk will get some TLC

One other question, is there an idle screw?...to drop the idle rpms

Thanks tyson

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PostSubject: Re: Briggs 12.5 I/C Carb Mixture Screw   Briggs 12.5 I/C Carb Mixture Screw Icon_minitimeThu Aug 12, 2010 7:34 am

Yepper - when you look at it from the top- the first plate inside is the choke- then behind that further in is the throttle plate - when its activated, part of it outside contacts a 'stop' - theres a screw that will lower idle speed. If that wont fix it, it could be an issue with the governer or governer link....
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PostSubject: Re: Briggs 12.5 I/C Carb Mixture Screw   Briggs 12.5 I/C Carb Mixture Screw Icon_minitimeFri Aug 13, 2010 6:09 am

What he said Laughing
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PostSubject: Re: Briggs 12.5 I/C Carb Mixture Screw   Briggs 12.5 I/C Carb Mixture Screw Icon_minitime

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