Vapor Lock 70 Dart Swinger 340 Car

maldridgeks said

I’ve attempted to re-create the problem twice, with one day being slightly cooler outside but the other was plenty hot. Came home and checked down the carb throats - they were dry. Buttoned car all back up and allowed to heat soak 20min or so, and still nothing in the carb throats. After checking the carb I went ahead and tried starting the car and it started just fine. After thinking on it, the only thing else that has changed is that I did refill the gas tank with non-ethanol fuel. Right after i filled it up, the problem did recur, but after running it a while (and possibly further diluting the older fuel that may have had ethanol), the problem appears to have disappeared. Thoughts?

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Winterize ethanol fuel make a "vaper lock" worst. Try to stick with non-ethanol fuel in the winter. If your carb is working correctly, the motor should start and once the bowl in empty, the motor will stop, in a vapor lock. I have a Dodge van with a 340 and installed a electric pump at the tank, to push the fluid to the mechanical pump. Problem solved. Vapor look is a carburetor issue. For those who don't know how it works, here is my explanation. When fuel heats up in the line, as near headers or exhaust manifolds, the fuel turns into an air pocket and will not let fuel be drawn from its source. Once the fuel is cooled to be drawn, or pushed, it will function correctly. The reason injected autos as of today do not have this issue, due to the fuel pump in in the tank.