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Category: Small Engine
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My Murray mower has a Briggs & Stratton engine model 31C707-0154-E1.

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My Murray mower has a Briggs & Stratton engine model 31C707-0154-E1. It recently started running very rough and spewing out large amounts of dark exhaust. Now it won't really run at all. If I can get it started it spews out exhaust for a minute before losing power and cutting off. I opened up the Head cover and it was full of fuel. I cleaned that up and also the spark plug. It ran well for a couple minutes before the problem returned.
Any ideas as to the what the problem is and can I fix it myself?


Hi, this is Russ, I'll be helping you with your problem today. THANKS! XXXXX HERE IS A CARBURETOR THAT IS FLOODING This due to a stuck needle or bad float. Remove the carburetor (**** DIAGRAM ALL PARTS AND LINKAGE***) Disassemble and place in good carb cleaner (NAPA) overnight minimum, reassemble with a carb kit from the local dealer. CHANGE OIL AND FILTER IF SO EQUIPPED. thanks good luck

Customer :

I cleaned the carburetor per your instructions and was able to get the mower to start, but after a few minutes it cuts out, So it doesn't seem like I accomplished very much.

Customer :

The engine still does not run. It will start but after a few minutes it cuts out. Is there away of adjusting the carburetor?

Category: Small Engine
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Just to try to help, If you DID NOT use a NEW COMPLETE carburetor repair kit when you cleaned the carburetor.....replacing the needle and seat, You just wasted your time. As Russ said, you must replace the needle and seat and use a complete carburetor repair kit. You allso may need to REPLACE the float....especially if it has any gas inside. Take the float off and shake it up to your ear and see if you can hear any fluid inside it. If there is, the replace the float. Also many of these carbuaretors have a BRASS seat that requires sppecail tools and know-how to replace. You may have to have a good repair shop rebuild the carburetor if this is the case.


Here is the parts list for your carburetor. There are two carburetors listed, you must choose whick carburetor you have.


Here is the complete service manual.

Briggs & stratton Single cylinder OHV service manual



{Please make sure that you click the ACCEPT button beside Russ's answer as this is the only way he will get paid. this is his question.)

Edited by Ranwell1 on 2/8/2011 at 7:25 PM EST
Customer: replied 6 years ago.
Thanks for the reply. It's been a while since I did this, but yes I did use a new repair kit. I replaced everything that I could - not the brass seat. I did not detect any gas in the float.
I fit has a brass seat in it, the problem is most likey that the brass seat is worn or has a slight chip in it. We as dealers ALWAYS replace this seat when we rebuild the carburetors because they usually don't wrok unless you do.

Edited by Ranwell1 on 2/8/2011 at 8:01 PM EST
Customer: replied 6 years ago.
so it looks like i have to take it to a repair shop after all since I don't have the tool to replace that brass seat.

There is a way that you cando it. Take a 1/4" tap and thread the seat. Then take a sleave and put it over the seat. then take a bolt and screw a nut onto the bolt. then screw the bolt it through the sleave (you should probably use a washer on top of the bolt) into the sear. then take the nut and tighten the nut against the sleave and it should pull the seat out of the carburetor and up into the sleave. You must make sure that the sleave is large enough that the seat will go up into it. then you must take the new seat and press iti in with a vise....usuing aontoer sleave or back end of a socket. Make sure that you goe tit pushed al the way in, but do not push it too far or you can break the carburetor.