Last Fall after a day of boating the engine of my 1987 Wellcraft 165 hp mercruiser starting losing power and seized up dead in the water. Would not crank, there was no overheat warning given as the gage was still at 165 when this happened. After being towed I went to check the problem the next day and the engine started up with no problem and runs fine in the driveway with the water ears on. No signs of any water in the oil and the boat has a closed cooling system and the coolant is full. I suspected a possible bad lower unit water pump but after taking it apart is was ok. The heat exchanger is new and not clogged The only thing I could find was a slight kink in the water hose that runs from the lower unit to the transom but water was still able to flow. I have not been out on the water yet to see what happens as I live near a river and I'm afraid of breaking down again with dams and barges I want to be safe. Has anyone heard of this happening to this motor and have any advise? I have ordered a new sender for the gage just in case it is wrong and a new thermostat. I'm hoping the engine cylinders wern't damaged too bad but like I said it runs fine in the driveway with no noise. Any advise would be appreciated.
Thanks,
Gary

I am not certain, for an engine to sieze while running that is usually alot of damage. Not even sure where to tell you to look.

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