First off I have a 1985 mercruiser 5.7 v8 350 I/O. As we were coming in today, the boat all of a sudden stopped. I was getting no alarm, but looked at the temperature gauge it was at 220. There was kind of a grinding sound when we stopped and the throttle was still engage, but the prop was not spinning. I come to neutral on the throttle, the grinding noise stopped, and when I put it back in gear....nothing. The prop doesn't spin, but the contols are shifting. I hooked the ears up and started her up, and no water was coming out of the exaust, and the temp gauge started rising quickly. The motor starts right up with no problem.....any suggestions???