I had a crack in the exhaust side, the fins had been hitting and scarred the shaft. I asked what would cause this he said, poor maintenance or shutting down after ahard run with out letting it cool. Or maybe just old, the motor was said to have 850 hours on it when I got it a year ago, and i may have put 100 hours in it, he said that was pretty low hours for this to go out. So maybe just a bad turbo? But he said this new turbo is more powerful and if i would like we could tweak the fuel pump and put out another 20 or 30 hp. had anyone tried this with a Ad41? any thoughts or experiences good or bad. Thanks Erik