Hey there guys, I just took my 1931 model a coupe on her maiden voyage after several mods. It has a factory drivetrain with a burns downdraft new 94 carb and mag with new wires and plugs. Puts around town and down the street all day no problems. Now here for the issue.... If i take it down the highway it makes it about 1/2 mile in high gear then acts as if it runs out of gas and dies... Pull over and wait 30 sec. And do it all over again. Im using factory tank and a fuel line to the 94. Is it possible because i had only about 2.1/2" of gas in the tank that theres not enough volume of fuel to force it into the carb at a sufficient rate? Im betting it runs down the highway till it runs the bowl dry? Town putting must not use the gas a highway run does?? Help please and thanks Posted using the Full Custom H.A.M.B. App!
Diagnosis sounds right. Problem is discussed on Ford Barn every so often. It is less of a problem with the higher tank of the 30-31's than it is with the 28-29's. An electric fuel pump would likely solve the problem. Mine is mounted on a bit of angle iron bolted to the frame below the carb. Sorry no pic, posting from iPad.
Are you sure the opening in the tank is clean. My old A used to clog up at the threads in the tank before having it cleaned. Acted a lot the same
The float bowl is much higher on what you have compared to the stock updraft carb. So there is not as much fuel pressure with no pump. It will help to keep more gas in the tank, but an electric fuel pump may solve the issue.
No the cap is solid with no vent but fits pretty loose so i dont know a if thats it. Ill give her a whirl with the cap off and see. I have had some crap in the threaded area so ill double check that. I dont really wanna put a pump on the old girl just yet. Thanks guys!! Posted using the Full Custom H.A.M.B. App!
I had to break down and add an electric pump on the same set up that you are talking about. I even tried a 3/8" line from the fuel tank outlet to the carb inlet. Just saying......
All 31 model A have a vent in the gas cap. Look inside the cap for a hole in the center part of cap. This vents on top of the gasket. Can not see on outside. This vent is a common cause of engine quitting.If you do not have this hole ,you may have a radiator cap on the tank.You probably will need a fuel pump,but you also need a vented tank.Good luck. John Posted using the Full Custom H.A.M.B. App!
When I ran the stock tank, I noticed someone, long ago had filed a narrow cut across the tank fill neck seal surface. A few early cars like Bugatti (others?) had a dash mounted fuel tank air-pump.
2 1/2 gallons would definitely not be enough pressure to maintain higher speeds. Mount an electric inside under het gas tank and no one would be the wiser. Or mount one of the air pumps.
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