Ok I have a 292 with a motorcraft 4300 4bbl and a after market replacement fuel pump. both are revelitve new and if started weekely work great. but if it sets for a couple of week I have to crank forever to get fuel back up to the carb. if i put a fuel presure reg on would this help? is there anything i could do to help this problem?? or is that just the nature of the beast? thanks

 

I have the same problem, I think the fuel is evaporating from the carburetor. My truck is a 1977 F150 with a V8.

 

Ditto what Chris said. Fuel evaporating is the "nature of the beast". The only other cause might be the fuel draining back toward the fuel pump, but that requires that the pump have a leaking diaphragm or valve. If it's fairly new, that is unlikely.

 

On the big grain trucks and the like we used to add an electric fuel pump that ran off a pushbutton on the dash. You would "prime" the truck before you started it. Ford even had one stock on their big industrial V8s.

 

I had the same problem on a 292 I put in a 46 Ford pickup years ago. At the time I thought it was a bad pump, so I installed an electric fuel pump. It started ok after that, and for the rest of the time I owned it.

Rod

 

This can also be because of a leaking power valve gasket. To check, pull the top of the carb loose after the engine has cooled, and watch the level. (leave the cover on but loose) Once the engine has cooled there should be little evaporation going on. On the Holley 94's (flatheads) this is common as dirt, the shape of the newer (replacement) power valves is different at the seat than the old ones, and a special gasket is needed to properly seal the power valve to the body. A bad gasket will drain the bowl almost overnight, and it all ends up down in the manifolds and cylinders, not a good situation at all.

The best gasket to use is an AN crush washer made of tubular copper, AN 900-8 (1/2" I.D.) .