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Serious Vapor Lock - Help!!!!

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  • Serious Vapor Lock - Help!!!!

    I've been driving my 54 champion six almost exclusively this summer. Problem is at 85 degrees, if I run it say 20 miles shut it off and come back in 10 minutes, the thing will start and run for about 5-10 seconds then die (sounds like fuel starvation). Even after much cranking, it may only cough a time or two but not start. Being six volt I don't have alot of cranking potential.

    Let it cool for 45 minutes and it will start right up.

    The intake, carb and associated area gets really really really hot, as I found out when it vapor locked on me and I had to drive it, I poured some gas down the carb and it immediately BOILED up and out! It was like cracking a hot egg in a frying pan!

    Engine runs about 185-195 degrees, checked with candy theromoter in hot radiator.

    Any thoughts here guys? I've tried adding diesel to my gasoline with not really much success and converting to 12 volt is not an option.

  • #2
    I've installed an in-line electric fuel pump on the frame with a hidden switch under the dash, to help push along the fuel. It's helped on hot days when the engine would begin to stutter.

    Western Washington, USA


    • #3
      Do you have the heat shield on the fuel pump? It does help, as does the electric fuel pump. If you don't have the heat shield, you can make one from aluminum sheet, there are plans around somewhere.


      • #4
        I've installed a return fuel line from just downstream from the pump back to the tank. The theory is that the fuel circulates, does not sit in the line getting hot. Not tried it out on the road yet, but idling, with the engine at 190, the incoming fuel line was cold to the touch. This probably won't help with heat soak when turned off, but it sure seems like it will help while running. The electric pump has already solved the heat soak problem.

        A heat shield should work well, too, the exhaust pipe and manifold radiate heat to the fuel pump (on a Champion) and no amount of moving air will eliminate that.

        Tom Bredehoft
        '53 Commander Coupe
        '60 Lark VI
        '05 Legacy Ltd Wagon
        All three Indiana built OD cars


        • #5
          I don't have a heat shield on the fuel pump or carb....I've heard of a design pattern floating about...anybody have a copy?


          • #6
            First thing to check is your exhaust heat riser valve. If it is stuck closed, the exhaust heat is constantly being routed up to the bottom of the carb. It will cause the symptoms you describe.

            thnx, jack vines



            • #7
              We have done the return line thing and worked very well. I too have had bad vapor-lok problems it got real bad today. I could idle okay but not run very long. Took me 15 minutes to literally go 2 miles with NO traffic. I have a switched electric pump on it and have even tried the diesel fuel remedy to no avail. Today I bought some Marvelous Mystery Oil as someone suggested so I will try that now. This is really a new problem for me, for years I have had no problems at all, all of the sudden its terrible must be the gas.


              • #8
                Dont forget the supply of gas from the tank to the fuel line: Restricted pick up tube in the tank, or a pinhole in the tank pick up tube. This masked as vapor lock for years on one of my antique cars.