Look at your fuel tank for 2 hoses and one electrical connection of 2 wires. The large hose is obviously the fill hose and the length helps to define if you may have the problems you describe....the longer, or if it has bends, the easier to cause the problem. The second is smaller, roughly ⅜" and that goes to your vent. Follow it back and it probably sits on the top of the transom so that any fuel that might spill out would go overboard. Since the fill hose is much larger in diameter than the nozzle on the gas pump, my thought is that the vent mentioned is more of an overflow device to prevent pressure from building up in the tank.....lets it vent to the atmosphere. The deck adapter should have a screen over the hole to keep foreign objects out. Then the two wires are tank ground...return and fuel level signal to the fuel gauge on the dash.
As I recall, on my last boat, built a lot like a tracker bass boat and same material, I had to go it slowly....Tank was 22 gal plastic and hose lengths were about 12" long or so.
