2005 Mercruiser 350 Mag - how hot?

[mattias]

I have a 2005 240SD with a Mercruiser 350 Mag. How hot do you typically run?

 

[bobeast]

Assuming you mean coolant temp. Mine usually run between 135 and 145°F. This is at my typical hull-speed (~1500 RPM)

 

[Espos4]

I have a 160 degree thermostat. It runs 156-158 degrees regardless of engine speed.

 

[Lazy Daze]

Yup, somewhere in the 160-ish range is normal/expected. Don't look for your numbers to be EXACTLY what someone else's is or even EXACTLY the same from time to time. If you're in that range, you're good.

 

[mattias]

Thank you! Should it have a 160-degree thermostat in it?

 

[Espos4]

Thank you! Should it have a 160-degree thermostat in it?

Raw water cooled came with a 160° thermostat.

 

[FLWestCoast]

I have a 2005 SD240 with 350 Mag. It runs just under 160. I had all sorts of trouble with overheating last year and eventually had a through hull intake installed.

 

[Todd Sing]

I replaced my Impeller and Sea Water pump, when I tested with muffs it overheated. Replacing the thermostat resolved this. It is a 160 degree thermostat, I run at 155-160 normally.

 

[Scott215]

@FLWestCoast
What kind of outdrive do you have. My 5.0 MPI 2006 alpha runs a tick over 170. New water and t stat. It's always ran that temp

 

[techmitch]

@FLWestCoast
What kind of outdrive do you have. My 5.0 MPI 2006 alpha runs a tick over 170. New water and t stay. It's always ran that temp

It's in his profile along with his location.