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Avanti overheating carburetor

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  • Avanti overheating carburetor

    My '63 R1 has an Edlebrock carburetor and shows signs of fuel boil when hot. Wants to stall after worm up and coming to a stop. Also shows hesitation on taking off. Always starts up again after stall. I have adjusted the floats and misture with no improvement. I thought an isulator between manifold and carb. may help but checking clearance from airfilter to hood doesn't give a safe clearence for more than a 1/4 inch insulator. Comments are welcome.

  • #2
    Heat riser stuck shut.

    Comment


    • #3
      My Avanti did the same thing without a heat riser. If you find that the heat riser is not the problem get some gaskets from Dave Thiebault that block the heat riser passages in the intake manifold. Unless you drive your car in freezing weather you will not see ANY adverse affects. Easy job to do with very positive results.

      ErnieR




      On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

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      • #4

        Ernie, I don't have any qualms about removing the heat riser, but have to contest your idea about closing off the manifold crossover totally. Cutting off the heat to the carb will not allow the fuel to vaporize properly. You need to have some of the exhaust pass under the carb. I believe the Avanti manifold gaskets had a smaller hole than the standard V8's, but it enhances warmup considerably and improves roadability immensely.
        Once started, it takes a fair amount of time for the engine to evenly stabilize temperature and the performance while cold is terrible. Prolonging it by isolating the carb on a cold manifold is just a bad idea, in my opinion and I wouldn't say that without experience.


        Bob Johnstone
        www.studebaker-info.org

        64 GT Hawk
        55 President State Sedan
        70 Avanti (R3)
        64 GT Hawk (K7)
        1970 Avanti (R3)

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        • #5
          In very cold weather my experience with a Mopar was that it took an extra long time to run properly but once things warmed up a little it ran fine.

          On the Avanti I don't even have a choke! However, it's not a completely fair comparison to an R1 because my car is an R2 and the discharge air from the supercharger is warmer than the air going in so I'm sure it helps driveability in the cold weather and I do drive it in the dead of a NJ winter if there's no salt on the roads.

          So I don't disagree with you but if the car is rarely driven in winter conditions the improved driveability in the warmer weather may be worth the stumbles in the winter. My car used to suffer the same maladies as Gary's now I can drive in 90+ weather with no stumbles or stalls and the same crispness as it does on a 70 degree day. I'm so committed to the blocked crossovers mine are welded shut for years now.

          ErnieR




          On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

          Comment


          • #6
            quote:Originally posted by garyc

            My '63 R1 has an Edlebrock carburetor and shows signs of fuel boil when hot. Wants to stall after worm up and coming to a stop. Also shows hesitation on taking off. Always starts up again after stall.
            Those don't sound like signs of "fuel boil" to me. Are there other symptoms that make you feel that is the problem?

            Dick Steinkamp
            Bellingham, WA

            Dick Steinkamp
            Bellingham, WA

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            • #7
              Before I blocked the crossovers the gas would boil up and dribble out of the secondary venturis. Even if it didn't get to the boil over point the vapors would richen the mixture up to a point where it would stall ( until I put the throttle kicker on then it would just surge ), and hesitate from a stop and belch a little black smoke on takeoff.

              And that was after I removed the heat riser.

              I think the underhood temperatures exacerbate the problem on the Avanti.

              I still say try the gaskets if the issue doesn't improve after checking the heat riser. Cheap and easy experiment.

              ErnieR

              quote:Originally posted by Dick Steinkamp

              quote:Originally posted by garyc

              My '63 R1 has an Edlebrock carburetor and shows signs of fuel boil when hot. Wants to stall after worm up and coming to a stop. Also shows hesitation on taking off. Always starts up again after stall.
              Those don't sound like signs of "fuel boil" to me. Are there other symptoms that make you feel that is the problem?

              Dick Steinkamp
              Bellingham, WA


              On its way to a 15.097 Island Dragway Great Meadows NJ Spring 2006.

              Comment


              • #8
                I'd have to go with the block off of the cross over. I've experienced the same boil over problem and cured it by filling the crossover with a furnace cement. Sounds crude but it worked. The block off gaskets eventually burn through. The problem was solved and I noticed no il effect. However, I don't drive in the winter.

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