Cooling systems - 240 DA

[isitsummeryet]

I have my 'new' 240 in the water finally and noticed last weekend that the temp was up around 165 - 169. My last boat ran around 140. the temp in the DA is steady and I read that this temp is normal for a closed water cooling system. Does anyone know if it is a fresh water or closed system? the motor is a 305 merc (alpha I)

 

[jimdavi]

Not sure about the 305 but my 5.7L raw water cooled runs at 158-160, and a closed cooling 5.7L runs at 170 per the mercury manual.

 

[tphinney]

never see a 240DA with closed cooling but it should be easy to tell. look at the front of the engine just above the serpentine belt. If there is a long round cylinder going horizontally across he front then it should be closed cooling. that round cylinder would be the heat exchanger.

but I don't thinkyou'll find one unless it was added as an after market.

on the other hand my 240DA normally runs in the 165-172 range and if you check the manuals you'll see that for the 305's the thermostats where either 165 or 175.

I think you're fine..

if you think it should be running cooler based on the water you boat in, you might want to look at changing out you're impeller. unfortunately on a Bravo I you'll have to pull the stern drive to do that.

 

[Quint4]

"unfortunately on a Bravo I you'll have to pull the stern drive to do that"....I didn't think any of the Bravo drives have an impeller in the outdrive. They are all mounted on the front of the engine...correct me if I'm wrong.

 

[tphinney]

Sorry quint;

your right. I meant the Alpha I.

 

[Nehalennia]

Does it look like this with the radiator cap on it?

This is my 5.7 and I added FWC.
170 is perfect temp to run at. The fact that you're saying it's steady there is a good sign too.