I bought a boat w a 83 140 hp johnson on it that ran on that boat. I took it off and put it on my bass boat. At full throttle it goes 6 mph. I put other throttle cables on it thinking they were kinked or twisted. Motor has 125 psi all around and spark. Starts on first try, but at full throttle goes 6 mph. I used my old controls and plug that was off an 86 150hp. The motor has a newer lower unit also. It just seems like something isnt in sync. i can move the throttle on carbs in neutral and it takes revs up full rpm. Any ideas.