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Surfer
07-02-2013, 10:04 AM
Hi,

what would be the right engine temperature for Mastercraft Pro Star 190 1995 engine (275 hp, EFI)?

The engine is raw water cooled, just replaced with rebuilt base engine.
I mainly ski in lakes, so no salt water. Water temp. most of the time <70 F.

With original engine the temperature was around 176 Fahrenheit last ten years, i.e. gauge pointer in the middle.
Now 149 Fahrenheit at most. Which sounds a too cold.
With 160 F. thermostat, could some parts of the engine run too hot?

Also:
In the original Mastercrafts Chevy / Indmar engine the head gasket passages for water were ca. 0.2 inches, not full size it could be. I heard this is because of raw water cooling could be too efficient -> thus the engine does not run too cold.
Wth the new engine I do not know what kind of head gaskets there are.


Thank you!

Traxx822
07-02-2013, 10:13 AM
I have the same engine. I just put a mercruiser brand 140 degree thermostat in it. I don't want to take any chances.

especially since I just put in new head gaskets this week.

You are fine.

etduc
07-02-2013, 12:13 PM
Hi,

what would be the right engine temperature for Mastercraft Pro Star 190 1995 engine (275 hp, EFI)?

The engine is raw water cooled, just replaced with rebuilt base engine.
I mainly ski in lakes, so no salt water. Water temp. most of the time <70 F.

With original engine the temperature was around 176 Fahrenheit last ten years, i.e. gauge pointer in the middle.
Now 149 Fahrenheit at most. Which sounds a too cold.
With 160 F. thermostat, could some parts of the engine run too hot?

Also:
In the original Mastercrafts Chevy / Indmar engine the head gasket passages for water were ca. 0.2 inches, not full size it could be. I heard this is because of raw water cooling could be too efficient -> thus the engine does not run too cold.
Wth the new engine I do not know what kind of head gaskets there are.
Thank you!
You're fine. T-stat rating i.e.-160 is the temp, when stat is fully open. The exiting water temp is from a sender located, on the intake manifold. Corrosion on the sender, can insulate the sender from water, giving a false reading(make sure it is clean).

The exiting water temp is dependent on lake temperature, and the condition of the engine block water passage condition. The older block probably had corrosion/rust, causing higher readings.

With a new engine and <70 degree lake water, you will not get to 160 degrees. If you want to run hotter water temp, you may consider a 190 t-stat.

In Texas, I have used 143 and (currently)160 degree t-stat.