overheating motor

i have a 1991 yamaha 2 stroke 90 hp that is overheating does anyone know what temperature thermostat should be in there?

also is there a way to test the teperature sensor?

[99yam40]

I am not positive about the temp but I think it is 140 degrees F.
It is simple to test in a pot of water that you heat up while checking the temp with a thermometer and see when it starts opening and when it fully opens and how far it opens. You can do the same with the sencer but it is a little harder to pull out

[jb123]

if you havent replaced waterpump and housing, stats and prv in the last year, you should.