Raw water cooling to fresh?

[barney]

How hard and expensive to switch? I have an 81 3LT merc I/O. Can it be done.

 

[tommays]

Re: Raw water cooling to fresh?

http://marineengineparts.com/shopsite_sc/store/html/page19.html <br /><br />if you do a search on the internet you will find many kits <br /><br />IMHO i think a 1981 motor is past the point when it will do anything because the block has so much rust after 23 years it may even be hard to keep the exchanger from cloging from rust flakes<br /><br />tommays

 

[barney]

Re: Raw water cooling to fresh?

It says it cools the block only, Does this meen that there is somthing seperate for the exhaust, actually the boat is an 81 the engine is a later model I forget which.

 

[tommays]

Re: Raw water cooling to fresh?

the manifolds will still be cooled with raw water they could be cooled with with a heat exchanger but it would be so big it would not fit in the boat so they only cool the block <br /><br />there are a lot of good things about fresh water cooling like not haveing to worry about the block freezing in the winter but again it depends on how old the motor already is <br /><br />if i was putting in a new motor or buying a new boat i would do it for sure<br /><br />tommays

 

[Boomyal]

Re: Raw water cooling to fresh?

The other good things about closed cooling are that you can run a 180 deg thermostat, which provides much more efficient combustion temperature. Also closed cooling systems eliminate the radical engine block expansion and contraction from eliminating the intrusion of cold raw water into the block. This is immeasurably easier on head gaskets, cylinder walla and piston ring wear.