Fresh water kit installation?

[joebar11]

I have decided to make the leap to fresh water cooling.
How involved is the installation of the kit and is it alright to do it while in the water?
What will I need to do to clean out the 30 years of crud in there now. I have back flushed a lot of black silt out and figure I will need to clean that out better as I make this conversion.
The clearance is no problem around the engine.
Thanks for all past and future advice.
JOE

[Don Moyer]

Joe,

I'm attaching the set of instructions which comes with our fresh water cooling kits to give you an idea of what's involved.

Don

[joebar11]

Thank you Don,
That certainly answers my install question.
Now I realize I must first resolve my current overheating problems. I have already changed the impeller, acid flushed, and added a raw water filter (never had one). This helped for a short time then I overheated again. Back flushing got out a bunch of black silt which increased my exhaust flow to about 2 gallons a minute (looking for 3-5 gpm right?). Then overheated again, back flushed again, more silt. Should my next step be removing the side plate jacket to inspect and further clean out and sediment? I was very intrigued by a post from last oct (http://www.moyermarine.com/forums/showthread.php?t=486) that seems to describe my situation very closely.
Thanks
Joe

[Don Moyer]

Joe,

It sounds as though you have a local blockage that keeps reappearing. I recommend that you go thorough the steps in this basic troubleshooting
guide:

Check first to see if you have a normal flow of cooling water coming out of the exhaust. A normal flow of engine cooling water will usually be sufficient to build up a head within the water lift muffler at idle to overpower the exhaust pressure, and result in a "batching" of the water out of the exhaust every second or so.

If you do not have a normal flow of water through the exhaust system and out the back of the boat, your water pump could be too weak to provide sufficient water flow; or you could have a restriction in a location that can limit the total flow of water. Examples of these restrictions include a blocked raw water through-hull, a piece of broken impeller in the elbow on the outlet of the water pump, a clogged manifold, a blockage in the inlet fitting to the exhaust system, etc.

If, on the other hand, you experience overheating while observing a normal flow of water out of the exhaust, you will have to look for a restriction that is preventing water from entering the block and preferentially moving through the by-pass hose instead. Examples of such a restriction are a blockage within the "T" fitting, blockage in the diverter cap inside the center of the water jacket side plate, or a thermostat that is stuck in the closed position.

You can troubleshoot the extent of a blockage in this location, as well as getting some short term relief, by clamping the bypass loop partially closed with a pair of pliers or a small "C" clamp.

NOTE: The bypass loop is the hose between the "T" fitting in the center of the water jacket side plate and the inlet to the thermostat housing. The short hose on top of the head between the thermostat housing and the manifold is not part of the by-pass loop.

If the flow of cooling water out of the exhaust reduces significantly as you clamp off the bypass hose, the restriction would be quite serious and will probably require removal of the water jacket side plate and/or or the thermostat for further inspection, cleaning, or replacement. In the case of lesser restrictions, one of our customers was able drill an 11/32" hole through the center of the "T" fitting and tap it with 1/8" pipe threads. He was then able to connect a garden hose to pressure flush the "T" and diverter cap to restore good flow. After flushing, he installed an 1/8" pipe plug in the hole.

Don

[joebar11]

I installed the kit this weekend (thanks for making it easy!). Unfortunately I am still creeping over 200 with any more than 800 rpm's. Raw water flow is great from the exhaust. Before closing the system I had removed the jacket and thermostat housing and thoroughly flushed, back flushed and cleaned those areas then installed a new thermostat. I have a ball cock valve between the jacket tee and t-stat and closing that does not help. The water hose leaving the engine and going to the heat exchanger gets extremely hot (of course) and the fresh water hose leaving the exchanger is barely warm. This leads me to believe there is not enough of the cooled water flowing through the exchanger and back to the engine. I was thinking my next step is to replace the old fresh water pump.
Before I do:
How can I best check the flow of the closed water system to see if the fresh water pump is the problem? Is it still just a matter of removing hoses at certain points?
Should I flush the heat exchanger to check for blockage from initial loose scale or any other crud? Is there a strainer in it?
Although this process is frustrating I think I am really close and it is so nice to know I can come home and get help here when I reach a dead end on the boat. Thank you for all of your hard work.
JOE

[joebar11]

Forgive me Don, upon further searching, reading and finding your manual, I realize the acid wash and flushing that I have performed were not nearly as thorough as your recommendations. I will follow your procedure next time down to the boat, in the mean time can my problem be the pump or the exchanger from my last post. Or can I not determine that until the block is properly flushed?
JOE

[Don Moyer]

Joe,

It's usually possible to determine (at least in gross terms) how well coolant is moving through the enclosed loop by removing the fill cap and observing the movement of coolant directly below the cap; e.g. lots of movement good flow, very little movement poor flow.

Before replacing the pump, you could remove the hose leading to the inlet of the thermostat housing and have someone run the engine for a few seconds while you check for flow and pressure.

If you have good flow from your pump, close the bypass, and still don't get good flow through the exchanger, it may be time to take it to an automotive radiator shop to be hot tanked for cleaning.

There is no built-in strainer in the exchanger.

Don