1967 Mercury carb problem? NEED HELP

[1967merc]

I just purchased a 1967 mercury 20hp. First outboard i ever owned. I bought it in the winter, the guy started it ( found out later not good to do out of water). When it got warm out replaced the impeller which was in a million pieces. But the reall problem is that the motor starts but soon as it is in gear and ur moving it seems to be dumping gas in the motor, and come out of a hole in the side of the carb. Replaced the float, needle and seats and no change! Talked to some people and they said to adujust the float level but there is no adjument , it's free standing it connects to nothing. It will run good at certain point's in the throttle but when wide open it sputters and almost seems to be missing. Drove it around for about a half hour and used 2 gallons of gas, seems to be a bit much for that motor. Sorry about the length of the post but NEED HELP. the carb seems pretty simple compared to others ive seen.

[1967merc]

Hellllpp!!!