Chevrolet Repair: fuel drainback problem, electric fuel pump, clear plastic tubing

Question
I built and own a Classic Roadsters kit car. I use a GM,ZZ4,350 cu.in.,355 hp. engine with a standard oem fuel pump and a edelbrock 650cfm, performer series carb. After a few days or longer of sitting I have to crank and pump for awhile to get fuel to the carb (for starting). Same day starts are no problem. Very low mileage and the problem has existed from day one. Is this normal? If not, what can I do? Would an electric fuel pump help?  

Answer
Is there a possibility that you have an internal fuel bowl leak within the carb which is emptying the carb of fuel overnight ?.

1. Next morning open the choke plate by hand and while watching for the spraying of fuel going into the intake when you manually open and close the throttle plate will tell you IF you have fuel in the carb bowl.

If you see NO FUEL during this process, An internal bowl leak is highly probable.

If you DO see fuel being emitted during this process, this eliminates the possible fuel bowl leak possibility.


Next test would be to disconnect the fuel line(s) at the carb and attach a clear plastic hose to the fuel line and set the open end of the plastic line into a suitable container and watch to see if you can see fuel flowing into the CLEAR plastic tubing as you crank the engine. You should have fuel within 2 to 3 seconds. If NOT you can purchase a ONE-WAY fuel flow valve of which has a check valve built into it to prevent the back flow of the fuel. I have seen several types of fancy clear glass/ chrome units like this that you can insert on the suction side or the pressure side of the mechanical fuel pump.


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