I have been through this before but seem to be getting a bit stuck on this one so hopefully I'm missing something and you guys may have some more ideas, motor is a 40 with a cast iron intake single carb. What I have done so far, tried 2 older pumps with no luck, checked the pump rod for length, replaced with new rod still didn't work, welded up an older rod to give it added height still no go, the rod is moving up and down enough to the point where it will pick the pump stand right off the intake. I also put a new line and fuel pump on as well. When I hand pump the fuel pump with a screw driver in a vise it makes suction with no problem, I tried putting the inlet line right in a can of gas and run the motor and still no suction, I tried filling the tank with air to get fuel up to the bowl still won't work, the only thing I didn't try was hand priming the pump on the bench which I have never had to do before. The rod is definitley going up and down quite a bit so I'm assuming the cam lobe is ok. Thanks.