19 HP, B&G Fuel Feed Problems

Discussion in 'Mechanic and Repair' started by CraftyRider, Aug 23, 2006.

  1. CraftyRider

    CraftyRider LawnSite Member
    Messages: 6

    I have a Sears 42 inch riding mower with a Briggs and Stratton 19 HP engine that runs great when I first start it up, but begins running progressively slower in a about a 10 minute time frame. I though I may have had a clogged fuel filter so I purchased a clear aftermarket model. As you can see from the picture the filter is 95% full of fuel before starting, but as time goes on the fuel level in the see thru filter empties to about 5%.

    If I turn the ignition off it won’t start back as if I have a vapor lock, but removing the gas cap has no effect. After 30 minutes of colling down about 20% fuel builds back up into the filter and it will start again. I readjusted the carburetor air for as richer mix and it helped a little. I’ve checked the fuel lines on either side of the filter and they’re clear. The mower is about 10 years old and has not seen much use as I hire my yard to mown when I travel on my job. I can only conclude I need to rebuild the carburetor. Any advice would be much appreciated.

  2. CraftyRider

    CraftyRider LawnSite Member
    Messages: 6

    One more pic

  3. mcwlandscaping

    mcwlandscaping LawnSite Gold Member
    Messages: 3,163

    at first i was thinking a vapor look, but, apparently you covered that already
  4. Eddie B

    Eddie B LawnSite Senior Member
    from gone
    Messages: 859

    it wouldn't be the carb if the fuel filter empties to 5% after running for a while... the carb comes after the filter. Is the filter sitting lower than the carb? Try raising the filter/fuel lines so they are above the carb.
  5. Idealtim

    Idealtim LawnSite Senior Member
    Messages: 939

    If its gravity feed [wich i think it is] then the line befor the filter is plugged or line is not pointing down enough. Try re routing the line higher from tank to carb should be a almost constant horizontal line.. if there is a filter or screen at the bottom of tank, that may be plugged also.
  6. Idealtim

    Idealtim LawnSite Senior Member
    Messages: 939

    P.s. Don't take apart the carb, thats not the problem!
  7. CraftyRider

    CraftyRider LawnSite Member
    Messages: 6

    I've verified the line is clear between the filter and tank. I'm not sure how to keep the fuel in a line horz. It has to drop down out of the tank and route under the floor board then back up to the carburerator.

    I might see if I can use Eddie's suggestion and pull slack from the tank and raise the filter itself. Appreciate everyone's input! :dizzy:
  8. Nosmo

    Nosmo LawnSite Bronze Member
    Messages: 1,216

    Try getting the fuel line at all points (Including the filter) higher than the carburetor. It sounds like if it is a gravity feed somewhere the level is just too low. Or it could be the level is too low and when you rev the engine up to a cutting speed the fuel line is actually sucking itself closed
    above the filter and after you stop the engine the fuel runs slowly into the filter .

  9. newz7151

    newz7151 LawnSite Silver Member
    from Tejas
    Messages: 2,419

    It wouldn't be gravity feed if your fuel tank is under the seat. May be time to rebuild the fuel pump on the front of the carb. Normally, when an engine is running (especially on a fuel pump unit) you may not see the fuel filter filled up because it's pumping what it needs and using it right away.
  10. CraftyRider

    CraftyRider LawnSite Member
    Messages: 6

    This sounds like a good possibility. I'm going to temporarily route the fuel line away the head and see if that helps.

    Also as Newz stated the fuel tank is under the seat so I'm hoping one of these 2 diagnosis is the culprit. Thanks again everyone. :)

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