Still looking for cause of heaing problem

[harley_c]

90 horse mercury 3 cyl thought

90 horse mercury 3 cyl thought problem was impeller but impeller still looks new line between power head and pee hole clear and pee hole clear i was told that if I have sand in power head it will block lines am planning on checking thermostat and popit valve any thing else to check? npo water through pee hole and still overheating in water and with muffs

 

[benjamin_jones]

Why do you say it's overhe

Why do you say it's overheating?

Is the alarm going off? Maybe a dud alarm sensor?

Have you used the garden hose to flush motor with the lower case removed?

Impeller can look "new". Better to replace it as matter of course and this just might solve the problem.