I need help with this problem. I have a 74 Ford 3000 gas tractor that runs perfectly for a while and then cuts out, sputters and dies. When it starts to sputter, there are air bubbles coming into the top of the sediment bowl, but the bowl is also full of gas. It also tends to die when facing up hill. I can sometimes keep it running a little longer by pulling out the choke. Spraying starter fluid in the air filter also helps, which tells me its a fuel system problem. I took the carb apart and cleaned it, but it actually looked fine. I'm wondering if the fuel pump may be the problem? Any help appreciated.