My rochester carb used to require priming (a little gas down the throat) after as little as 2 days. I replaced the Rochester with a YF-2100S Carter, and put on a new fuel pump. Now it may take a little pedal pumping and a few extra spins of the starter after a week, but NOTHING like what it used to require.
For what it's worth, I think the check valve in the pump was bad, and the gas in the line would drain back down to the tank. With a little evaporation from the bowl, it would take a lot of cranking (or a little gas down the throat) before she would fire.
I suggest you try replacing your existing fuel pump, and if that doesn't work, try replacing or rebuilding you carb.
Kurt
