Hey Guys,

My 59 F100 with a 390 Holley 2 barrel, leaks fuel onto the manifold (pass side)
within 24 hours of using the truck. The carb (the carb is new) has been pulled off, checked, serviced, new gaskets installed. There is no fuel leak when the engine is running. The "puddling" occurs only as the engine cools down. It has so slowly I cant see where it leaking from. The fuel float site does not leak when I remove it. In line fuel gauge reads 6.5. Does anybody has any ideas why this happens?

Thanks in advance, Kevin

 

Check around the accelerator pump. I have had a leak like that with a pinhole in the diaphragm.

 

agree with above...................also make sure the diaphragm is alcohol safe......the blended fuels tend to eat the non-alcohol units up very fast especially when sitting

 

If the suggestions from the other members don't work, I would replace the needle and seat in the float assembly. Then make sure the float adjustment is spot on. While you are at it, just go ahead and replace the float itself. It may have a leak.

I recently installed a nicely rebuilt Autolite 2100 two barrel on my 292. The new carb had somewhat similar leak issues possibly coming from the breather hole on top of the float bowl. The above listed repairs were tried with total success.

 

Thanks for your suggestions guys, much appreciated! Ill give em a try

 

Along the same lines as needle & seat, check that the fuel tank cap is properly venting and not causing positive pressure to build in tank.