I have a question about my mercruisers first time out

[maharg]

So we went to the lake this weekend, had a good run, but I have a question. Our boat has a 140hp 3.0L, We ran at 4k rpm most of the time and the engine temp would barely hit 130 (then it would drop again), I know the user guide give 160 as the operating temp. Do I have anything to worry about? Should I do anything?

Edit, guide says 140 for op.temp.

Seems like maybe its ok, the temp gauge does move +/- maybe my gauge is off?

 

[imported_TheMan]

Re: I have a question about my mercruisers first time out

Make sure your thermostat is actually installed/operating.

A missing thermostat is sometimes a trick people use to mask a cracked block.

 

[Yellow Yota]

Re: I have a question about my mercruisers first time out

Check your thermostat. Probably stuck open or missing from the time it stuck shut on a previous owner.

 

[jtmarten]

Re: I have a question about my mercruisers first time out

If the t-stat is missing or stuck open, it can show the engine is running cool, when in fact it might be overheating. The water flows through too fast to pick up heat and cool the engine.
The cooling system is not like car's system where the coolant will recycle through and eventually pull heat and very inefficiently cool the engine.
The boat is pulling cold water through and back into the lake, so the water is always cold coming in. It has 1 shot to grab heat and keep the engine cool.

 

[maharg]

Re: I have a question about my mercruisers first time out

Edit, guide says 140 for op.temp.

Seems like maybe its ok, the temp gauge does move +/- maybe my gauge is off?