The Stovebolt Site Forums The Shop Area Engine Shop 235 runs good until...fuel delivery? Carb? Vapor?

My 59 runs perfect after the rebuild of the stock engine and carb. HEI ignition added I have driven 500 miles in the last few months with no problems until last week.

Drove about 20 miles on a hot afternoon and when I let off the gas pedal to slow down for a turn, the engine died and would not restart for 30 minutes. Sure seemed like it was not getting any fuel to carb. Choke did not help and finally 30 minutes later it ran good al the way back home. Now the last two times I have driven it more than a few miles AND ONLY WHEN I LET OFF THE GAS PEDAL, the truck dies and won't restart for about 10-20 minutes with no hint of gas. The letting off the gas pedal has me puzzled?

What do you think? Does the letting up on the gas pedal and dying then indicate a carb issue created by the sudden loss of vacuum or sound fuel pump related. There is no stumbling or missing indicated at all before this happens. De-celerate and she goes dead for a while....float? It has been hot.... vapor lock?

If it takes 30 minutes to restart you will have time to trace the source of the problem. Take the fuel line off and put a fuel pressure gauge on the line and turn it over to see if you have fuel pressure. If you have pressure take the gauge off and put a hose on and run it to a bottle or can to see if it has volume. Be careful so you don't dump gas on a hot engine and start a fire. If all this checks out put the line back on and tap the carb at the fuel inlet and see if the needle and seat are stuck. Try starting it, if it goes you have found the problem. If it still doesn't start try putting a little gas into the carb and see if it starts. This will get you started.

Does the truck idle okay?
If it does, and assuming you are in gear (not clutch pushed in) you draw a high vacuum in these situations. It is possible you are actually flooding the engine under these conditions if your float level is a little too high or your needle and seat is leaking. Can you smell gas when you are trying to start the truck. Have you tried cranking it with the throttle held wide open?

Chuck

Thanks guys. The truck idles fine and I am just about sure it is not flooding as I get zero gas smell and absolutely no evidence of gas making it to carb body. I am going to check fuel flow and volume but wondered if the sudden death happening only when I let off the gas pedal was a good clue to point towards vapor lock or carb issue as opposed to fuel pump related.