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Closed cooling

cyana

New member
Hi everyone,
I am new to boating and to this forum.
As i am planned to install a new engine (MarinePower 5,7V) i have a question about the cooling system.
The engine will be used in seawater and is equipped with a closed cooling system (glycol).
The seawater coming out from the heat exchanger goes into the risers (correct me if i am wrong) and into
the exhaust and leaves the exhaust together with the exhaust gases.
As a motorbike (not a boat) mechanic it doesnt make any sense to me to mix the hot salt water with the exhaust gas
and let it run true the exhaust pipe. '(maybe only to cool down the exhaust pipe a bit)
I am thinking to redirect the water coming out from the heat exchanger to a plug in the hull instead of into the exhaust.
What are the pro's and con's for this?
 
As Bondo said, you need the cooling. You will quickly burn out your exhaust hoses and fiberglass exhaust sections, causing a major fire and carbon monoxide hazard. Also you may possibly make the exhaust noise illegally high. In a properly cooled system the risers should be only warm to the touch.
 
Agree!

It sounds as though you have what's called a "full system" (exhaust manifolds are also E/G cooled).
For an I/B or I/O, it is a requirement that from the elbow/rise back, the exhaust must have the sea water flow in order to maintain the correct temperature.


Salt begins to crystallize at/near 140*F. Your "spent" sea water (if all is working correctly) should not exceed this.


Remember that if you are in an area where winterizing is required, your elbows/risers must be drained during winterizing.
 
Sea water goes into the heat exchanger and then dumps out the exhaust riser.

Glycol water circulates through exhaust logs, and into the block and back in a loop circuit.

The only thing that salt water will therefore rot out, is the riser, providing the heat exchanger is a proper design and most of them are brass and won't be affected by salt. Risers are often cast iron, and therefore they only last a few short years in salt water. IF you get a stainless steel riser, then you are good to go for the long haul.

regards,

Paul
 
The only thing that salt water will therefore rot out, is the riser, providing the heat exchanger is a proper design and most of them are brass and won't be affected by salt. Risers are often cast iron, and therefore they only last a few short years in salt water. IF you get a stainless steel riser, then you are good to go for the long haul.

With the seawater (salt water as you said) passing through the HE's tube bundle, and being in contact with any cast iron, we will see some galvanic action occur while not running.

Keep up with pencil anode replacement, and you'll lesson the likelihood of damage.
Often pencil anodes require several replacements per season.





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hello I am also a new member - I am looking for the following information
what is the plumbing config when changing over to fresh water cool on small block mercruiser - where do the salt water hoses hook into the manifolds?
 
hello I am also a new member - I am looking for the following information
what is the plumbing config when changing over to fresh water cool on small block mercruiser - where do the salt water hoses hook into the manifolds?
Rather than hijack this thread, best to start a new one for your specific questions.
Give us as much information as possible.

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