"Gene- If this problem hasn
"Gene- If this problem hasn't occurred since the beginning, you should find the actual nature of the problem. How long since the impeller was changed, have you been in water that had a lot of loose sand or did you drag the drive through silt? Even if it was in neutral, the motor running would cause a lot of sand or silt to be drawn into the motor and when it settled, it hardened enough that when the water came through later, it didn't dislodge whatever is in the motor.
You didn't give enough info for anyone to make any kind of informed diagnosis. The best thing you can do is make a list of any problems, quirks or events that may have caused this. List all of the service that has been done on it since you got the boat. If there hasn't been much done to it in the past, start with doing all of the scheduled maintenance. If it overheated, there's a reason for that and it should be addressed. If it froze, that needs to be dealt with, too. If it was run out of the water with no water to cool it, if it was more than about 15 seconds, your impeller may be toast. Don't just replace parts with different values just because it's running hot without looking for the cause.
FastJeff- as an example, Indmar doesn't use anything lower than 160° on their motors and a lot of them are in Mastercraft, Malubu and Supra/Moomba tournament ski boats. We both know that running at higher temperature makes the motor burn the fuel more efficiently. With the new emission standards, I don't know how a motor with a 140° thermostat would meet them. "