Do It.Best desision you will make. so quite, No smoke. My Yamaha four stroke has close to 800 hours on it now and has not had a hicup. Never stalled once from the time I hit the Key. You will start trying to hit the key while the motor is running in idle to start as you dont hear them idle. Mine is a F150 so heaps bigger but I love the Yammy four strokes. Will be going on every boat of mine. And my Last motor was a 90hp Johnson Ocean runner about the same age as yours. They are a great motor also but you just cant compare the fuel Econemy, Noise , Smell etc. They are magic
Dave