1999 Mercury 115 alarm

[KebMo576]

I have a 1999 Mercury 115. Twice now after long wide open runs, a constant alarm sounds just after slowing to trolling speed. When I shut it down the alarm goes off and 2-3 minutes later I can start the engine and the alarm will stay off. Motor is peeing and oil tank is full. Any ideas?

 

[Chris1956]

Easy stuff, the motor is overheating. Rebuild the waterpump with an impeller two gaskets and a wear plate. Check the waterpump base for overheat and scratches. Replace it. If the waterpump cover has scratches, replace it.