Like the title said, it's getting hot.

So here is what is happening:

When I bought the boat, it didn't pee very hard so I changed the water pump and fixed that. Now, when I'm just idling across the lake, the temp gauge creeps up to hot. Haven't had the alarm go off yet. When I get up to speed, it cools back down to normal temp.

I'm thinking "thermostat"?

I try to do all the work myself as I'm pretty handy with cars, but just wanted to see if someone with more experience than me could chime in and either confirm my suspicion, or give some other direction to try

you can check the thermostats in pan of hot water(with thermometer) ,all they do is open and close.(around 140 degrees)
also, the older merc's will slowly get hotter at a fast idle 1200 plus..( no-one really runs at idle lol )
reason is the "popoff " valve (opens up full flow) does not open until about 1500 to 1800 rpm.
run it at real idle , and if it doesnt heat up , you are probably good to go .
if it doesn't heat up above 2500 rpm , that is normal op for the popitt valve.
hope this helps

no alarm?.. whats normal?.. install a water pressure gauge.... get a "temp" gun to test accuracy.... gauges are notorious for being inaccurate...

whats temp gauge reading

Normal is a tick over middle on the temp gauge



When it gets hot the temp gauge is pegging out on hot but the alarm never goes off

oiler still on it?.. if so, do ya get tha self check beeps?.. have ya checked tha over temp sensor/buzzer?.. poppet may not be seating at idle/low rpms...

Oiler has been removed. I mix oil when I get gas directly to the tank. Haven't tried checked the over temp sensor

I would change the Poppett valve

This is very normal to run warmer at idle.