After sitting awhile, my car’s hard to start
I have a late ’60s Ford 302 with an Edelbrock four-barrel and new fuel pump, and everything concerning the motor is newly rebuilt or replaced. The car runs fine but after sitting for a while it is hard to start. I have noticed the fuel filter is always dry after sitting overnight, and it seems I have to allow fuel to be pumped up to the carb before it will start. I have checked the automatic choke and it is functioning properly. Occasionally the fuel in the float bowl may be enough for the car to start, but if the initial crank does not allow starting, then I have to crank until fuel reaches the carburetor. What am I doing wrong?
Provided you pushed down once on the accelerator pedal to set the choke before cranking, I doubt you did anything wrong. Check the float level in the carburetor and make sure the needle valve is seating properly. After eliminating those possible problems, I would hook a pressure gauge to the fuel line going from the fuel pump to the carburetor and make sure it is consistently providing the correct fuel pressure according to your shop manual. Most vacuum gauges can also measure pressure, and they are available at auto parts stores for a modest price.
If the float level is too low or the needle valve is not sealing properly or is sticking, the carburetor will not retain enough fuel to maintain a sufficient supply. And if the fuel pressure is inconsistent or not high enough, you will have problems too, although I would be surprised if the fuel pump was the problem if there was no trouble once the engine is running.
In any case, I would install an electric fuel pump near the fuel tank and hook up a switch so you can flip on the pump to fill the carb float bowl. That way you won’t have to crank the engine over and over to get fuel up to the carburetor after the vehicle has been sitting. You would then switch the pump off once the carb has enough fuel.
You could also go to an electric fuel pump full-time and dispense with the mechanical one, but then you would need a pressure regulator because electric pumps generally provide higher pressure than mechanical ones. And the blank-out plate that goes where the mechanical fuel pump had been would cost you points at a car show.