I have a late 90s Mercury Black Max 150 horse outboard motor never been in saltwater just freshwater put it on water heaters and water coming out of the pee hole is about as warm as good bath water temperature put your hand on top of the heads where the thermostats are at and you can lay your hand there all day it's warm but not hot run it in the lake and the water coming out of the pee hole is so hot you can't touch it tested the water temp there water coming out was 140ish degrees heads you could still lay your hand on top of the heads and it was warm but not too hot to touch water temperature at the lake was 83 that day boat runs great no misses or hiccups but water coming out of the pool is super hot should be that hot coming out of the pee hole