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Briggs & Stratton 42A707-2238E1 flooding out

Discussion in 'Mechanic and Repair' started by swamptiger626, Sep 27, 2012.

  1. swamptiger626

    swamptiger626 LawnSite Member
    Posts: 6

    So I have this problem enging that keeps flooding out on me. I rebuilt the carb twice which had no effect do I bought a brand new briggs carb and installed it, still no change. Through the process of fighting with this motor I have replaced the starter, battery, plugs, air filter, and fuel filter. I now have installed a fuel shut off valve next to the carb and have to shut the fuel off and let it die out in order for it to start up again and not flood out. This is a very annoying process and I would love to get it resolved. Any suggestions?
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    How long does this machine sit between startings, With-in minutes of shutting it off ?

    Or like when you finish mowing and park it for a week or two then go to start it again ?
     
  3. swamptiger626

    swamptiger626 LawnSite Member
    Posts: 6

    It sits about a week
     
  4. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    If I'm not mistaken, that's an old opposed twin and the carb has a vacuum operated fuel pump. When you replaced the carb, was the new carb supplied with a new fuel pump assembly as well. If you simply swapped the old fuel pump onto the new carb, you may have a diagphram/gasket leak, particularly if the fuel tank location is high enough to provide gravity flow.

    Just an old timer's stab in the dark.
     
  5. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    I just kneeew the "old timer" would sniff this one out ! :waving:


    swamptiger,

    Here's my thought, If your parking this machine inside of a closed up garage/out building, The gas cap may not be venting properly. Most are designed to let air in.....With excessive heat pressure can build in the tank and cause fuel to be forced from the tank to the carb and past the float needle valve into the intake.

    I've seen this happen a few times with machines just sitting outside the shop in the sun......
     
  6. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    I was just applying the SWAG Theorem, Rob. :laugh:

    As per usual, your scenario is probably more likely than mine.
     
  7. swamptiger626

    swamptiger626 LawnSite Member
    Posts: 6

    The new carb came with a new pump as well. And I wouldnt think it would be pressuring fuel into the carb because I have fuel shut off valve. And yes it is one of those opposed cylinder jobs with the diaphragm pump on the carb
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Let me spell this out for ya.....



    Sooo...... Does it still flood with this valve turned off ?



    Me thinks you need to check/replace your gas cap......
     
  9. swamptiger626

    swamptiger626 LawnSite Member
    Posts: 6

    Wow, cant believe that one went over my head lol. I'll check that today and let you know something later on, thanks.
     
  10. rm25x

    rm25x LawnSite Member
    Posts: 187

    I have had several come in that would flood out and actually fill the crankcase with gas on some occasions depending on how high the fuel tank was mounted on the machine. The fix is to replace the needle and seat. Not just the needle, but you have to replace the brass seat as well. To pull that, I put an ez out into the brass seat, then put the end of the ez out in a vise. Then hit the carb body with a rubber mallet and the seat will pop right out. I then use a socket on a short extension to drive the new one in. Make sure its all the way seated into the carb body.

    I think I had to do at least a dozen of them this last season.


    Edit: Sorry I just re-read that you installed a new carb as well and still have this problem so it's probably not a needle/seat issue in your case. But I want to keep the info here in case anyone else has the same problem. I would replace the fuel cap or leave it loose overnight and see if the problem goes away like was suggested. Just like a gas can that puffs when sealed, the fuel tank will "puff" with no venting and push the gas past the needle/seat.
     
    Last edited: Sep 28, 2012

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