I have an old Johnson outboard model RK-25D Really disappointed how slow the motor pushes the boat. I think i have found a problem in the linkage. At full throttle I noticed i still had about and inch and a half more to go back at the motor. Made the adjustment hoping to test it when we have enough water here to launch. Does anyone know what horsepower that model number is? Can't seem to find it anywhere. The boat is a fiberform about 15 foot. The boat won't come up on the plane. Motor seems to run ok. was thinking about trying a different prop. thanks conkee1