I dont know the serial # or model # off the top of my head, all I can do is describe whats going on. I have a 1990 Johnson 150 GT on a 1990 Ranger 482V. When I got the boat it would run 6000 rpm at wot, and 57 mph on gps. I have a 13-1/4 x 23pitch shooter prop on the boat. I put a hot foot on the boat myself, and tried a 24 pitch prop. Ever since then the boat wont get up on plane, it will rev up to about 3500 rpm and stand on its butt, but wont get on plane. For some reason when you put a load on it it wont rev up, it does the same thing when I try to put it on the trailer, it dies. I took it to a mechanic, he rebuilt the carbs, put a new power pack on, new pluges and wires. He said he got it up on plane but it was slow about doing it. I took it out and it took for ever, my dad had to get up on the bow of the boat for it to get up on plane, and then it would only run about 5000 rpm. Something is not letting it run enough rmp to get up on plane. If you are in neutral and rev the motor it will rev up to 5500 to 6000 easy and the same with the muffs on, but for some reason when you put a load on it, it cant get up. I have been told by some older guys that my exhaust could be partialy stoped up. Does this make sense, or is there anything else that could be doing this. Its been this way for 2 months, I am about to give up!!!![]()