I would dis connect the fuel line from the carb and run the fuel pump if electric or turn motor over if machinicle sp. then work your way back to the fuel pick up dis conecting fuel filters or seperators, till problem is found. if nothing you have 2 choices and I would go with the # 1
#1 "Long fix" remove fuel tank from boat, flush tank, check for rust and junk clogging the pick up, Its not easy pulling the tank so I would recomend replacing the pick up, pump and sending unit while you have it apart possibley up grade a bit "I always do but you dont". then reasemble. sucks I know. most of us go through this in our old school boats, or will. also be sure to check for a vent line and that it works correctly. No air in the tank, no fuel out, while running. You can customize your tank to just have a pick up and sender and run a electric pump in a place easy to get to for matanince sp. mount at the lowest level possibe, electric pumps dont suck as well as mechinical, they push real hard. so try and mount bellow fuel cell or level with the bottom of the fuel cell.
# 2 "Quick fix" blow air into the fuel line twards the tank, remove filters first, to blow junk out of the pick up & tank if possible, add fresh fuel with fuel treatment to help break down what ever is in there. And if the pump is bad I heard of people running a second fuel pump leaving the bad one it there. mechinicle or electric. mec is alot cheeper.
