I have a 1986 4winns 19' with a mercruiser 3.7L, 190 HP. The motor was running fine when put away last September, it will not start because no fuel is getting to the carburetor, the gas line is disconnected from carb and nothing is coming out of the mechanical fuel pump when cranking over. the motor runs then dies with starting fluid, any suggestions on what it could be? The gas tank is full.