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Briggs Carb, fuel pouring out

Discussion in 'Mechanic and Repair' started by Big-O_S13, Aug 9, 2007.

  1. Big-O_S13

    Big-O_S13 LawnSite Member
    Messages: 3

    I have a 19.5 horse briggs motor I'm having problems with. I used the mower about a week before and did not have any problems the I tried to use it three days ago.

    Motor starts fine and runs for about ten seconds then fuel starts coming out of the two vent holes right in front of the main air inlet of the carb-->motor floods out-->engine dies:confused:

    If I disconnect the fuel line, it'll run real good till the carb runs out of fuel.

    I rebuilt the carb ,cleaned it out real good (let it soak in carb cleaner,used compressed air in all of the holes) and it still does the same thing.

    Help!!! Any input would be greatly appreciated.

    Briggs 42E707-2631-E3
    4 Bolt pump
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Did you replace the float needle valve ?
    Did you check the float for fuel inside ?

    Either of these could cause this problem.
  3. Big-O_S13

    Big-O_S13 LawnSite Member
    Messages: 3

    Yep, I replaced the needle and checked the float (made sure there was no fluid inside and turned it upside down to make sure it was parallel to the upper part of the carb)
  4. mike lane lawn care

    mike lane lawn care LawnSite Bronze Member
    Messages: 1,707

    if it has a fuel pump, it could be sending too much fuel into the engine
  5. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 963

    Did you also overhaul the fuel pump portion of the carb?
  6. Big-O_S13

    Big-O_S13 LawnSite Member
    Messages: 3

    yes, the parts were included in the carb rebuild kit
  7. willymoeP

    willymoeP LawnSite Member
    Messages: 2

    O, did you get the problem resolved? If so, can you tell me what you did to fix it? I have the same mower with the same exact problem. I've been working on it for about a week. I installed carb rebuild kit with fuel pump diaphrams and I have had the carb apart 4 or 5 times to make sure I wasn't missing something simple but don't know what to try next. Thanks!
  8. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    From looking at a breakdown of that carb and from what I recall, I'm thinking that carb has a nonremovable brass seat. I have had reasonable success in beveling a wooden q-tip at an angle comparable to the needle tip, lightly coating the q-tip with valve grinding compound then lapping the seat by hand or slowly with a cordless drill. With the upper carb body in the inverted position the needle and seat should hold a pressure of 5+ psi. If you have a pressure tester you might check a before and after.

    And as Rob indicated check for a leaky float.

  9. WreckRman2

    WreckRman2 LawnSite Member
    Messages: 8

    Actually that brass seat is the cause of a lot of leaky problems and it can and should be replaced.

    Part Number: 690577 (for most engines)

    I made a seat remover that's basically just a long self tapping bolt with a nut and a spacer. The space needs to be wider then the seat itself. You then screw the self tapping bolt into the old seat then tighten the nut against the spacer and it will pull the seat upwards and out.

    Use a hammer to LIGHTLY tap the new seat back into place.

    I change about 5-6 of these per month in the field.

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