it could be a pluged fuel screen on the pick up tube in the tank. or cracked and or pinched fuel line. make sure the rubber hoses back at the tank are good. this is what I do to prime the fuel line before I start an engine that has a fuel problem. take the fuel line off at the carb. have a freind hold it in a can. take the gas cap off, and wrap a rag around a blow nozzel of your air hose and put it in the filler neck of the gas tank. then slowly blow air in to the gas tank (be careful not to put to much air pressure in the tank)and have your freind watch to see if there is any fuel coming out of the fuel hose. if no fuel comes out then the line is pluged some where. if it is pluged some times you can blow air back through the fuel line from before the pump to the tank. you should hear air bubbles in the gas tank.(never blow back through the pump as there are check valves in the pump and it will be bad for the pump). also is there gas in the tank (just thought I would ask)I have also seen the pickup screen come off the pickup tube and not pickup any gas till it had half a tank or better.one last thing if it has been setting for awhile I have seen the neddle and seat stick closed and had to bang on top of the carb to unstick it. hope this helped and not confuse you.
