Originally Posted by greysailor
Just a quick check before you yank it off and spend a boat buck......Have you popped off the air filter to see if you can spin the intake blades? It may just have soot/rust blocking the exhaust side blades.
If the turbo doesn't spin easily, remove the exhaust elbow so you can look inside the turbo throat.
If soot then look at what may be causing that- over propping would be the most likely cause. But excessive black smoke/soot rarely blocks up the turbo.
If rust, then it most certainly is sea water backing up from a poorly designed exhaust system. You need to rework the exhaust so that the lowest point of the riser is 12" above the water line and the injection elbow drains to the exhaust and doesn't leave a slug of water in it to corrode it out.
If you don't fix the foregoing, you will be paying for another turbo rebuild again at some point.
Turbos in well designed exhaust systems rarely fail by themselves.