Answer: The fact that it starts, and continues running with the help of gasoline being poured into the carburetor tells me that there is no problem with the ignition system or fuel pump. I believe that what is happening is that while the car is sitting idle for a couple of weeks, the fuel in the carburetor bowl is evaporating leaving the bowl empty. At the same time, the fuel in the fuel lines is draining back into the gas tank to some degree.
I’d be willing to bet that if you try the following procedure, the car will start. Crank the engine for about ten seconds. Pump the gas pedal to the floor three times. You won’t flood the engine by pumping the gas pedal because there is no gas reaching the carburetor…..yet. Keep repeating this. You will probably have to repeat it at least ten times, but the engine will eventually start when gasoline finally reaches the carburetor. That is if your battery doesn’t die first. For obvious reasons, this is not the greatest practice to ensure the longevity of your starter or your battery, but it will demonstrate that the engine is capable of starting on its own without pouring flammable and volatile fluids into your engine.
This is somewhat of a common problem caused by the fact that gasoline simply evaporates over time. The only sure-fire (no pun intended) solution is to install an electric fuel pump in the fuel line that runs from the fuel tank to the engine. This is accomplished by removing a small section of fuel line, usually alongside the frame rail, and replacing it with the electric fuel pump. You can leave the rest of your fuel delivery system intact.
Alternatively, you can remove the existing mechanical fuel pump, install a “block-off plate” in its place and use your new electric fuel pump to deliver fuel to the engine. Make sure that the fuel pump delivers pressure in the range of 5 – 7 psi or install a regulator. If you leave your existing mechanical fuel pump in place, wire the electric fuel pump through a switch on your dashboard because you will only need it to get the engine started and then you can shut it off. If you choose to eliminate you mechanical fuel pump, wire it into your ignition since it will need to be on any time the engine is running.
This may all sound very complicated, but it’s actually quite simple and it works perfectly.