I recently overhauled a 1982 Enticer 250 and everything works fine but it won't draw the fuel into carb. I bought a carb kit, everything is cleaned up, purrs like a kitten when primed but cuts out after burning off primer. Won't draw fuel up to carb. Fuel will move up and down a little in tube but not all the way. Seems to have good vacuum. Any ideas? Thanks!!!!!