I have a 1986 fabuglas. I bought the boat used and have no info on motor size etc. I know it is an omc 4 cyl with a cobra sterndrive. My quetion is how do i find out what is the best prop size to buy. I am currently running a 13x19 aluminum 3 blade but when i accelerate with any weight in the boat it is extremely slow to get on plane. I dont plan on skiing with the boat but i do want to have a lot better takeoff without sacrificing too much top end. Any help will be greatly appreciated.