Connecting fuel line to carburetor

Can you siphon fuel from the line? If you cant suck fuel from the line, the pump wont either.

Assuming you have enough fuel in the tank? Assuming the line isnt clogged/kinked somewhere? Assuming you have fuel crossover valves - and they are set right.

Have you checked your fuel filters and/or water separators? You may have a water sep on the block, and a fuel filter back by the tank.

Do either of your engines work? You mentioned that you pulled the carbs - but not why. Was any other work done? Was the boat winterized? Is this a new to you boat? Not alot to go wrong between the tank and the fuel pump.

Know anyone with a mightyvac? Adapt some hoses together to attach it to the incoming line to the fuel pump (line from the tank) and see if you can get fuel. Or siphon the ole fashion way and re-live the experience of tasting gasoline.

Don't think you have them, but anti siphon valve at fuel tank (if you do have one) may be NG.

Also, possibility the "sock" at the end of the fuel pickup in the tank may be plugged / contaminated. Have pulled some out of fuel tanks and they were absolutely disgusting. Crap fuel created a huge brown blob on the pickup screen.

Edit / Update: I checked my '95 220 yesterday and it DOES have an anti siphon valve. I would check yours to see if it is present and if it is operational.