i have a 1978 200 series 20 hp merc it starts first pull and idles really well but as soon as i give it gas it bogs out and dies they only thing i can see wrong is the air fuel mixture screw is siezed and i cant turn it or should i even be able to is there a fix or do i need to find new carb not sure if i can get screw out and how any suggestions would be great thanks.
