How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask RUSS Your Own Question
Category: Small Engine
Satisfied Customers: 3666
Type Your Small Engine Question Here...
RUSS is online now
A new question is answered every 9 seconds

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

Customer Question

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?
Submitted: 5 years ago.
Category: Small Engine
Expert:  RUSS replied 5 years ago.


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
Satisfied Customers: 3666
RUSS and other Small Engine Specialists are ready to help you
Expert:  Ranwell1 replied 5 years ago.

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 5 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.
Expert:  Ranwell1 replied 5 years ago.
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 5 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.
Expert:  Ranwell1 replied 5 years ago.

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.


JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Previous | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland

Meet The Experts:

  • Curtis B.

    Curtis B.


    Satisfied Customers:

    have worked on and around most engine models for 35 yrs./Polaris ATV expert
< Last | Next >
  • Curtis B.'s Avatar

    Curtis B.


    Satisfied Customers:

    have worked on and around most engine models for 35 yrs./Polaris ATV expert
  • Rick's Avatar


    Factory Authorized Trainer

    Satisfied Customers:

    Outdoor Power Equipment technical trainer since 1990, covering eight states.
  • Jon K.'s Avatar

    Jon K.

    Small Engine Diagnostic Expert

    Satisfied Customers:

    Gold certified Stihl tech, Service Manager for a rental/repair shop.Certified in most small engines
  • James W's Avatar

    James W

    Small Engine Troubleshooting Expert

    Satisfied Customers:

    7 years as Mechanic & Parts Manager for Brother who has Owned Lawn & Garden Repair shop for 35 years
  • Vince O.'s Avatar

    Vince O.

    Small Engine Technician

    Satisfied Customers:

    Over 30 years experience repairing lawn and garden equipment. Chainsaws, mowers,blowers and trimmers
  • RUSS's Avatar



    Satisfied Customers:

  • Wayne's Avatar


    Engine Rebuilder

    Satisfied Customers:

    many years on egine rebuilding, lawn mower,roto tiller,Truck,and small engines