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Fresh water system diagram hamilton 212/6.0 MP vortec

scenicjetboats

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Does anyone have a detailed diagram/schematic on how the fresh water system is assembled? Let me regress. I need to put a sand filter/trap on this system but I also want to flush it. I have sucked a lot of sand thru it. Also yesterday froze it and burnt exhaust hoses. It has been cold here (20* high 0* low) for a couple days. My guess is the fresh water heat the cold inner coils and it instantly froze plugging the fresh water system and not cooling exhaust. Temp went to 200* and we noticed smoke in exhaust from burning hose. I shut down immediately. Any thoughts if I am right on the cause of this? If s how does one prevent it? Also curious easy it is to remove the coils from the reservoir tube. Not sure how it is held in and clamped so the coolant and fresh water don't mix.
 
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I believe that your post hasn't received replies for a number of reasons. Firstly, are you talking about a Hamilton Jet engine? Marine Power engine owners might not be familiar with this. If you do have a Marine Power engine, the Marine Power website has an owners manual with closed cooling system diagram on page 41. It will closely resemble most closed cooling systems.

The second reason that folks may not have answered is because they may think you have done major damage to your engine by not winterizing if temperatures have fallen to 0 degrees Fahrenheit. You may have ruptured hoses, lube oil cooler, heat exchanger, exhaust risers or raw water pump. Burnt hoses indicate a serious lack of raw water cooling. I highly recommend closing your raw water seacock to prevent boat flooding and having a qualified mechanic examine your system as soon as possible.
 
Let me take this a bit further. I forget this forum focusses more on engines than the whole picture. The boat is a 06' North River sled powered w/ a 6.0 MP vortec engine and a 212 Hamilton jet pump. The fresh water system is self winterizing 'IE self draining' so there is no need to winterize for storage. Obviously an issue with freezing weather start ups. It is not a true closed system but coolant was good for -20 so that part of the system is good. The jet pump feeds the fresh water cooling part of the system. That is the system I am trying to learn about as I would like to pull the coil out of the exchanger but am not sure as to how it is assembled or attached. No holes in the exhaust hoses but I will replace as a precaution. I also have issues with rocks plugging the fresh water line and am looking for a way to get around that.
 
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The piece you want to add is called a strainer...made by GROCO, PERKO, and several others...you apy for quality components so don't get a "cheap" one - the aggrevation will lead to extra expense...

The heat exchanger is usually "soldered" together...most don't have a "coil" inside but a series of tubes that makeup the container for the coolant portion of the system...

The coolant side works like an auto system...the "raw water", from the river, is drawn in by a pump, passes thru an oil cooler and then to the heat exhanger. From there the normal path is to get dumped into the exhaust elbow - the specific path driven by the cooling system design used.
 
Makomark, Thanks for the input. I have attached an image of my engine. So on the heat exchanger it has bolted caps on the ends. Isn't this to remove fresh water coil or is it for ??
images_jetpump3.jpg
 

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You have a "full" FWC system...this means the exhaust manifolds are in the coolant side of the cooling system.

The end caps are removable so you can "brush out" the raw water passages within the heat exchanger. Under the caps, you will likely find dividers that form chambers that will redirect the raw water so it makes multiple passes thru the exchanger...If you have sucked up a lot of sand, don't be surprised to find some of it in the lower chamber(s), too. if you are going to pull the end caps, it would be best to get new gaskets beforehand...standard practice is to replace the gaskets vs trying to reuse them...Finally, many heat exchangers use sealing washers on the center bolts of the caps...take it apart slowly and replace any of the 'soft parts'...
 
Makes sense, THANK YOU. I don't mind tearing into things but sometimes it is nice to see if someone else has a clue before screwing something up. I'll order gaskets and see what type of mess is in there.
 
I like to refer to these a "Closed Cooling System"! (I know..... my pet peeve :mad:)
The term Fresh Water Cooling (aka FWC) is somewhat of a misnomer in that there is nothing at all fresh about Ethylene Glycol and distilled H2o. :rolleyes:
Fresh water can be interpreted as though a Marine engine is being cooled via Lake/River water.... and I get that one.
What I refer to as in a misnomer fashion.... would be regarding a closed ethylene glycol system being called FWC.
Perhaps some day the industry will get this right! :mad:


If you truly have a Closed Cooling System, you'll have two sides to the system.

1... the sea water side....
2... the E/G (ethylene glycol) side, of which is totally captive.

Generally speaking, restrictions occur (spelled over-heating issues) within the sea water side, ranging from restriction issues with the incoming sea water, to restrictions at/in the "spent" or "outgoing" sea water side.

Mark is correct.... you have what's called a shell and tube heat exchanger unit. The tube bundle is NOT removable by average Joe. These parts are silver soldered together during assembly.

The removable ends caps allow you access to the sea water side of the shell and tube unit, as to gain access to the ID of the tube bundle.
The most that we can do here, is to "rod out" the tubes, should they become blocked or restricted.
The OD of the tubes, or tube bundle (the E/G side), is not accessible by average Joe.

Take a look at this... it may help you understand the system better.
 

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To continue a bit...... (I got time out from my previous posting)

I realize that your sea water supply is via your Jet Pump, and would be in lieu of an otherwise I/B or I/O style sea water pump for many of us others.
Nonetheless, your closed cooling system, and your wet exhaust system, should not know the difference in terms of spent sea water volume, potential restrictions, blockage, etc.
Your idea for a strainer, in theory, should work like a champ.


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Ricardo, Appreciate yours and other posts. So I'll pull caps and flush tubes and do a visual inspection. Going to install sand trap. Then I think I'll contact Hamilton jet on the issue of the fresh water intake off their pump and see if there is something I can do to improve the performance of the fresh water intake point.
 
Did you mean engine cooling water supply port from their pump????

Yes, there is an outlet line on their jet pumps that feeds the fresh water cooling system. Most of my running is in the upper Willamette river and in shallow water I suck up small round rock and sand. The filter will take care of the sand but I have on occasion sucked up material that plugs the fresh water line till I can shut off motor and let it fall free. The problem is if you plug that line up but have to continue on power till you get into deep enough water to shut down you can over heat. I am trying to overcome that issue.
 
The problem is if you plug that line up but have to continue on power till you get into deep enough water to shut down you can over heat. I am trying to overcome that issue.
There may be a very simple solution for you.
 

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You might think about installing something called a sea chest. It is basicly a box, open to the outside but sealed to the inside, where you attach your intake hoses. In conjunction with a good sized Perko srtainer, you shouldn't have any debris any more. I would not be taking any cooling water from the jet pump. That's like crazy.
 
You might think about installing something called a sea chest. It is basicly a box, open to the outside but sealed to the inside, where you attach your intake hoses. In conjunction with a good sized Perko srtainer, you shouldn't have any debris any more. I would not be taking any cooling water from the jet pump. That's like crazy.
I like your idea.

And yes, I too don't care for the idea of the sea water coming from the jet drive.


Scenicjetboats....... back to the intermittently plugged up jet drive sea water source/supply:

IMO, I would think that your immediate over-heating concerns would pertain to your rubber exhaust components.
Your Heat Exchanger system will keep engine tempts maintained for a short duration.... very short, but will provide cooling for several seconds, if not a tad bit longer.

Perhaps the Johnson crankshaft pump, along with a thru-hull pick-up unit, would be a solution for this potential issue.
Something along the lines of the "sea chest", or a Perko sea water strainer, could be added in line to the crankshaft pump inlet.
groco_stainer.jpg





Updated image
 

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