625 AVS leakage

You may be right, but my money is on evaporation. The fuel formula was changed a year or two ago, and the ethanol or oxygenation additives make the fuel evaporate very fast. It's for better atomization and emissions. Holleys have a bowl where all the fuel for the jets and accelerator pumps comes from the bottom of the bowl. Carters and edelbrocks have the jets on the floor, but the accelerator pump is a little higher than the floor of the bowl. So the level drops as the fuel evaporates faster, and you are left having to crank the engine a few times before any fuel reaches the accelerator pump and meterring circuits. An electric pump will fill the carb before you turn the key. My truck w/a thermoquad does it when you dont drive it for a few days. I dont mine cranking it a little, then hit the gas twice.