what temp stat?

[hotmerc]

does anyone know what temp thermostat i should be running in a 1998 4.3 mercruiser. its raw, salt water cooled. its got 160 degree in it now, which i beleive is too warm. cruises at 180-190 degree's. in my mind is too hot. would running a 140 or 142 stat hurt anything? thanks...

 

[I/O WALDO]

Re: what temp stat?

Nope!

 

[AaronG]

Re: what temp stat?

My 1996 5.7LX came with a 160. It is also raw water cooled and exclusively run in salt water. It would run right around 160, and if I slowed down from a long run, it would go up to about 180 briefly then go back down to 160. Over the winter I replaced it with a 140. I figured the thermostat was 9 years old and due. The mercruiser dealer said to use a 140. <br /><br />Now the boat runs at 140. It never goes up past 140, and the engine compartment is noticably cooler after I'm done running the boat. <br /><br />I would use a 160 if the boat comes out of the water after each use and you flush it. <br /><br />If its in a slip like mine, I'd use a 140.

 

[I/O WALDO]

Re: what temp stat?

140 keeps the salt from comming out the water and depositing inside the engine.

 

[AaronG]

Re: what temp stat?

Running the engine at 140 degress is too cool to properly atomize the fuel. That means you get lower fuel economy,and increased ring/cylinder wearn I'm pretty sure Mercury went back and forth between 140 and 160 over the years on the raw water cooled engines. <br /><br />I don't think there is any problem using a 160 stat in saltwater as long as you are flushing it every time, and its actually running at 160 degrees.

 

[hotmerc]

Re: what temp stat?

with a 140 degree stat i don't think my engines will run at 140, but i think they will run around 150-160, which is what i'm looking for. i'm going to try it and see what happens. thanks guys.