1957 Fleetwin 7.5 TOO MUCH PRESSURE

[lumberjackleetch]

I've been working on getting my 1957 fleetwin running. I cleaned the carb and installed a new float. Put everything back together and it runs for about 10 seconds at high rpms and then it seems as if my fuel tank is building too much pressure, and that is forcing too much fuel into the carburetor and it is flooding the motor and literally flowing out of the carburetor. I've gone through the carb several times and I don't see anything wrong. When the carburetor is flooding I can see fuel coming out of the nozzle in the center. Any advice would be greatly appreciated. Thank you

 

[F_R]

It is highly unlikely it is building too much pressure. In the first place, it only receives the running pressure created in the crankcase, which if memory serves is about 4 psi. In the second place, there is a pressure relief valve in the fuel tank, which admittedly could be tampered with.

Have you replaced the float valve?

 

[racerone]

Have to agree , there is no way that there is too much pressure.-----Repair the issue with the float or float valve.

 

[lumberjackleetch]

Has anyone had problems with their fuel tank creating too much pressure and making fuel flood and overflow the carburetor?

 

[oldboat1]

That would be a problem with the carb float (or rather the mechanism -- valve not closing).

 

[jimmbo]

For the 4th Time, Take the carb apart, and inspect the Float and Inlet Valve. Adjust and/or Replace as needed

 

[F_R]

Has anyone had problems with their fuel tank creating too much pressure and making fuel flood and overflow the carburetor?

No way in hades could it build that much pressure in only 10 seconds. It just physically impossible for the crankcase to develop that kind of pressure, much less run and feed it to the tank. But if you really believe it is, you can test it with a pressure gauge. Some creativity required to hook it up. OMC once sold a special tool to do the job. Not so much to look for too much pressure but to look for not enough pressure.

 

[racerone]

Is this motor running with a pressure tank or has it been converted to a fuel pump ?

 

[kbait]

When you check carb, be sure the float chamber is vented to atmosphere (air in float chamber needs to vent to allow proper fuel level in float chamber to avoid overflowing). Not common for that vent to clog, but it will cause your issue, as will non-sealing float valve (MUCH more common).
Good luck!