Broken prop shaft

[JoshOnt]

I was out in deep water (for inland lakes anyways) and suddenly the motor just reved very high and I fell off plane. After trying to restart the motor and shift into gear I thought the lower unit was a bust turns out my prop shaft broke and took the prop with it to the motor. Anyone have ideas why this might have happened? Don't think we hit anything and never notice an issue with the prop shaft before. Also anyone had this or something similar happen to them?

 

[Frank Acampora]

I had this happen with a Force engine.. I ran around at cruise for several hours and when I started to go home I opened her up. The prop shaft broke immediately. In my case it was at the weakest point, the splines that are driven by the dog clutch.

You probably were the victim of metal fatigue.

 

[JoshOnt]

I had this happen with a Force engine.. I ran around at cruise for several hours and when I started to go home I opened her up. The prop shaft broke immediately. In my case it was at the weakest point, the splines that are driven by the dog clutch.

You probably were the victim of metal fatigue.

Yeah I would not doubt that, old motor, know it has been rebuilt once then ran for 1000 hours? Sucks but so is life. Have to replace motor since finding a replacement shaft and prop is next to impossible for a 77 merc 50 hp