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over 40 mph surging


mikzjr@aol.com

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I have a 29 chrysler model 75 with a BB-1 carb that I had rebuilt, new plugs, gas tank and vaccum tank sealed, gas is 1 month old was running good went for a ride this weekend about 40 miles but it started surging when I got over 40 MPH and the power dropped off when climbing hills, when I would get to the top of the hill and stayed at 40 or under it would smooth out. I got the car back and played with the carb, it smelled like it was burning rich, at the carb when I would give it gas it would hesitate a little but no matter what I did in adjusting the carb the hesitation was still there, could a vaccum leak cause this. Seems to idle smooth no popping but is rich now wasn't before the ride.

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Look for two things...small particles of flaky rust in the line or a vacuum leak. I had the same problem with an old truck. It would idle beautifully and when I started going the rust flakes would flip up and create a smaller opening in the fuel line cutting the fuel flow way down. Did you replace the fuel lines?

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Airplane or racing gas has way more octane than you need for an older car plus has different additives that may cause a problem, stick with plain regular. I'd still check for a vacuum leak, I had the running rich problem with my Pierce and it turned out to be bad manifold gaskets. Also, if you do not have a gas filter you should, I added one under the hood in the line going from the main tank to the vacuum tank. Good luck!

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Don thanks for the input I do have filters, What I tried yesterday I let the car idle once I heard the vaccum shut off to the vaccum tank I shut the car off open the tank it was full I disconnected the fuel line going in to the tank and sealed off the vaccum line then ran the car still the same problem.I going to replace the carb gasket to the manifold and the one between the adapter and carb. There is a adapter between the manifold and the carb that may be warped.

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