Gas pouring out of carb

Discussion in 'Fuel and Air Systems' started by Batesy, Oct 5, 2018.

  1. Batesy

    Batesy Well-Known Member

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    75 Dart Swinger
    Holley 1945 carb

    So my car has been driving great for most of this year. Suddenly out of nowhere I went to start it and it started OK but seemed to be idling wonky. Then when I hit the gas to engage the kick down it just died and then I could hear gas coming out of the carburetor at the base. So I took the carb off and inspected it. There were two screws in the float bowl that were loose. So I tightened them down. I figured that was the issue. But when I started it up it did the same thing. It’s not a trickle it’s like an avalanche. The carb was rebuilt probably a year ago. The gasket on the bottom is still in really good shape. I’m totally baffled.
    Here is a video moments after I started it and then killed it.
     
  2. diymirage

    diymirage HP@idle > hondaHP@redline

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    well, the good news is your fuel pump is working fine


    hardy-har-har

    i dont see a fuel filter in the video, i take it you have one?

    my next step would be removing the float bowl and carefully inspecting the needle and seat
    too high a fuel pressure can force fuel around the needle but it is much more likely that you got some junk in the there and the needle is not properly seating and that is allowing fuel to pour through

    now, when you say the carb was rebuild, the big question is...who did it?
     
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    • krazykuda

      krazykuda FABO Gold Member FABO Gold Member

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      Pull the needle and seat and look for some debris... Clean them off and reassemble then and see what happens...

      One piece of dirt that gets caught in the needle and seat will stop the flow of fuel when the bowl is at proper level and it will flood the bowl of the carb with gas... On Holleys it usually comes out the top vent tube like a water fountain...
       
    • Murray

      Murray FABO Gold Member FABO Gold Member

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      Probably you have passed dirt into the carb which has caused the needle and seat to hang open, flooding the carb. You need to disassemble the carb to clean it out and replace/install a quality fuel filter between the pump and carb.
       
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      • KosmicKuda

        KosmicKuda FABO Gold Member FABO Gold Member

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        I had the same thing on my /6 with Carter BBS last summer. Took the top off the carb and removed the brass float and shook it. Uh oh, it was leaking and gas was inside causing it to be heavy enough that the needle wouldn't seal against the seat.
        I drilled a small hole and shook the gas out and redoldered the seam and also my drain hole. Seemed to work but meanwhile I ordered a new float from Daytona Carb. Sure enough it did it again so I installed the new float and everything should be good for another 50 years. This could be a result of the gas they make us buy eating stuff up.
         
      • 70Duster440

        70Duster440 Well-Known Member

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        ...and make sure the float has no fuel inside of it. It's happened to me.
         
      • j par

        j par Well-hung Member

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        Believe it or not I had a piece of a cheap plastic fuel filter break off and go inside and plug up the needle on my float and of course it just let fuel poor in there.
         
      • Batesy

        Batesy Well-Known Member

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        Well, I took the needle valve out cleaned it really good and put it back. Same problem. I took it out again and this time I remembered that I had an extra one from another 1945. Tried that and the same problem. And just to be clear this thing is definitely leaking out the bottom.
        I guess my next thing to do is to pop it open and check the float.
        Thank you so much for the input so far.
        I will report back once I do.
         
      • j par

        j par Well-hung Member

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        I've had a float get a pinhole for whatever reason and sink. Also I've had them get stuck down for whatever reason. Get hung up or just gummed up.
         
      • AJ/FormS

        AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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        And I've seen the bottom oxidize to the point of seeping clear thru the aluminum.
         
      • Batesy

        Batesy Well-Known Member

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        The float seems fine. I even took it out and submerged in water to see if it would Show any leaks.
        Question: Is it possible for the fuel pump to be the culprit? I mean it’s worked fine for the last three years since I’ve installed it but is this something someone’s encountered before? Could the fuel pump just keep pumping too much fuel? Or too much pressure?
         
      • j par

        j par Well-hung Member

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        So you can put it all back together now and same thing? I haven't heard of a stock fuel pump going berserk and just pumping the hell out of the carburetor before? But that's just one man's experience.
         
      • Batesy

        Batesy Well-Known Member

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        Yes. Put it all back and same thing. Frustrating to say the least.
         
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        • j par

          j par Well-hung Member

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          This is one of those things where I wish I was there. The card looks clean and looks to be in good nick. It almost looked as if fuel line had a leak. Or maybe the spout where the fuel goes in is not sealed properly? I'm seriously reaching here because again I wish I could see it and the video is what it is.
           
        • Batesy

          Batesy Well-Known Member

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          I had a spare Carter carb that I switched out the Holley with and the problem followed. So i knew it wasn't the carb.
          So, a friend of mine who is a mechanic said he had actually had situations where somehow there was a blockage in the fuel return off of the pump that caused the fuel to back up in the carb. So I took the return line off the pump and blew some air into it (listening at the tank with gas cap off. It didn't appear to be blocked, although the shot of air may have dislodged it. So I went ahead and replaced the fuel pump and my problem was gone. I will never know if the fuel pump was the problem or if there was something that got lodged and broke free after I blew air into it. But she's driving fine now.