I had the same problem. I have a 200 HPDI Yamaha with a 4 blade Yamaha prop. I spun the hub twice. I talked with Bo's prop shop. He said the first time he fixed it, that I might want to look for a 2nd prop. He was right. I only have 72 hours on the motor. It spun the prop at 32 hours the first time and 72 hours the second time, both in deep water. He said the same thing, exhaust heat. I went with the new Mercury Prop. It has a square plastic incert and can be changed out real easy.I have not been able to run the boat for a good test ride, due to work. I still have the 4 blade as a 3rd back up. The 2nd is a new plastic incert. I looked on the boats at the sportsman show and alot of boats still have the old yamaha props.
2220Pro w/ 200HPDI, 80#MinnKota, 24volt onboard charger, Garman 541s, And a Huge Smile