1989 merc 5.7 temp?

[Dan_az80]

So i was out this weekend in the boat. The water temp was friggin cold (around 45-50*). The highest temp i would register on the gauge was 120*. I read somewhere that the normal operating temp for this engine is between 140-160*. Just wondering if not having a t-stat will cause this, and if so, can this be a bad thing?

 

[keith4216]

Not having a t-stat is allowing the cold water to flow thru never giving the motor a chance to get to temp.

 

[Jetmate]

That has been a controversial issue for years. Most jet drives don't run thermostats and the engines run cool. I have discussed this with some race boat builders I know and they say they run their Jersey Racing Skiffs with no T-stats. 120 is about all your gonna get with no stat, especially if the water is cold.

 

[Gimme Fuel]

It is ok for a block to run cool like that provided that oil temps once the engine is "warmed up" stay in the 170-190 degree range. There is nothing wrong with that. If you dont have an oil temp gauge i suggest adding one unless you put the stock thermostat back in and all is well.

 

[fasterdaddyfaster]

Fixed.

Multiple problems. This engine was not running Cold but actually running very Hot. The incorrect gasket was used so the Temp Gauge was not grounded properly so it barely got a signal so it would register only up to about 120. Put the correct gasket in and the temp climbed to 150, 160, 170, 180, 190. The thermostat was an automotive 190 degree. Put in the correct Mercruiser thermo and now it runs between 150-160.

 

[Jimway]

Left hand in front and right hand in front, both palms up, about 32 inches apart, nearly chest high.

 

[corey331]

What the.....wait....... what?

 

[fasterdaddyfaster]

Somebody confused???

 

[corey331]

A 4 year old thread gets dredged up out of nowhere by a different member saying the problem is fixed. Is just throwing me for a loop.

 

[RNGRDVE]

I know Dan sold his Enchanter so I'm going to assume this is the new owner.

 

[fasterdaddyfaster]

Bingo!