Last Friday I sheared off the propeller shaft and propeller on my Johnson 150hp outboard. I believe the shaft fatigued because I was in 30+ ft of water and no evidence of anything visible that I could have hit. ..still trying to figure it out,. My question is, the marina mechanic says I should replace the complete lower unit vice replace the shaft because salt water got into the lower unit and will pit the gears immediately.There is a significant cost difference that is having me question the need for complete replacement.
