not a third gen but my boat has a 305 in it with a 2bbl rochester. need some help seems to be running rich and choke dosent disengage anyone know how to adjust these

 

The choke on a boat is USUALLY a hot-air style. Draws hot exhaust gasses off the exhaust system or the exhaust crossover between the heads in the intake manifold. The choke element itself is usually pretty bulletproof- they don't go bad too often. However, the tubes that draw the hot exhaust gasses into the choke housing can get plugged up. Or the internal vacuum port inside the choke housing can get crudded up (the vacuum port actually draws the air through the tubes and into the choke housing).

Assuming that's working correctly, adjustement is by loosening the 3 screws that hold the choke element inside it's housing on the side of the carb and rotating the choke element to increase or decrease choke closing force. Hopefully your carb has screws, and not rivets. If it's got rivets you'll have to drill them out and put some self-tapping screws int their place to make it adjustable.