90hp inline 6 mercury tower of power

[Nova]

I have been working on my 86 hydro sport bass boat with 90 mercury tower of power. serial number a124493 We it sat out of gas for probably a year. I just replaced all the fuel lines, cleaned the tank. well i took it out and it ran ok idled in gear fine and drove ok. When i got back to load it up it died and didnt want to start i finally got it started but everytime i put it in gear it would die. I loaded it by hand and got it back home changed the plugs everything ran great on the hose could tilt it up far before itstarted to leak gas out of the carbs. well i took it out fired it up and ran great but when i went to start it up later that day about an hour or 2 to go back to the ramp it died everytime i put it in gear.it would die. if i pumped the ball hard i finally got it to run and drove great until i went to load it and as soon as i tilted the engine up to load it died. i notice hear at the house it would leak gas/drip from all 3 carbs if i squeeze the primer ball very hard.

[boats.net]

I would remove and clean all the carbs, may need to replace float valves in carbs since it sat for so long.