[Zackattack]

I have a 350 Chev in my beautiful Mariah, but I need a fresh Water Cooling system added, we do a fair amount of salt water trips and do not want my engine to ever see that abuse.

I was hoping to not have to spend the 800 bucks on a new one, but wondering if anyone has had experience adding this on theirs and if I should just bite the bullet and do it right or find a used one and try and match it up.

Thanks for your input.

[ShabahZ280]

Are you referring to a "Closed Cooling System"? A "fresh water cooling system" draws water in, vs. the closed cooling system, which uses antifreeze, and no raw water intake. Adding a closed cooling system will be an expensive job, and I recommend not trying to do it on a budget. Do it once and do it right.

You can also look into the Volvo Penta Neutra-Salt system, it's an add-on system that contains a salt neutralizing solution for engine water intake. It's pretty slick, and only costs a few hundred. That might be a better option for if you're only occasionally in saltwater.

Just remember a closed cooling or neutrasalt system only works for the engine, it does nothing to protect the outdrive from salt corrosion.

[Zackattack]

Thank you for the info, and maybe I am just a victim of a local reference to the two systems. We refer to the system without an expansion tank as a raw water cooled system, and the fresh water cooling is in fact fresh since it is a closed loop as you refered to it as and does not allow the raw water to cycle through the block.

And it is true that the raw water does travel through the outdrive and through the heat exchanger, it is still much better for a block for it to not have the exposure to actual sea water. The outdrive is fitted with sacrificial zinc's and requires a good flushing each time used.

That is the first I have heard of the system you refered to, I will look into that. There is a pretty large boat show here in Seattle next week and maybe someone there will have a presentation on the system.

Here in the Pacific Northwest it is rare for a boat to not have this already, although the one and only previous owner of this boat only used it in a lake and I would prefer to have the Puget Sound as a place to play as well.

Thanks, and I agree it best to do it once and do it right, even on a budget.

[Zackattack]

Well, I bit the bullet and bought a nice new San Juan engineering fresh water cooling system. This is quit an involved addition to the engine room. Unfortunately I broke one plug that needed removal from the intake manifold(was able to drill and easy out this one with some brazing torch heat). And now have gotten to the last two plugs in the exhaust manifolds that need to come out so they too can get the fresh water for cooling, and now both of those are so brittle that the air wrench I chose to use, tore em up. I tried big breaker bar and brazing tip on torch first, to no success.

So now I'm going to take the boat to a professional bolt extractor I know from my work to pay to have these removed and then I will be able to complete the install.

Oh yeah, the nicely bent mercruiser fuel line that goes from filter to carb was in the way by 1" and had to take to custom line shop and they made me s new one that avoided the bracket for the expansion tank. I was surprised that was only 40 bucks and looks perfect.

Will post a complete review and some final pics when I get her done.

Prop went to shop to get perfectified too, boating days are almost upon us!

[Zackattack]

Well, she is all wrapped up and back to running.

Purchased a new San Juan Engineering Fresh Water Cooling system(full kit with header cooling), and just completed the install.

It was a bit more involved than I was expecting, but went ok despite the obstacles.

The instructions from SJE are less that excellent, but if you read them 2500 times you will understand them. Upon install of new equipment, realized the original fuel line needed a new one bent a different direction to avoid the expansion tank and then the oil filter that mounts on the riser bolts on port side needs to have spacers and longer bolts to give at least one more inch space under for the hose to the header and from the riser.

The plugs in the headers were the worst part, they fell apart, and were siezed in there. I had to take the boat to a bolt extractor to have him finish tapping the threads so the fittings could go in properly.

All in all though, very pleased and just in time for spring, if it ever arrives. It runs very well at 160 degrees+- and seems to have great flow both in the raw water side and the fresh side.

Anyone have any specific questions, feel free to ask, I took some pictures along the way. Here are a few of the completed project.


san juan.jpg

engine stbd.jpg

engine.jpg

enginept.jpg

before engine.jpg

[harrisdm]

Hi zacattack,
I installed a Sanjan Engineering closed cooling system on my 1999 z302 with a 502 bravo 3 when my boat was new. I have not had any problems with it. But some words of caution(also noted in your manual). After running awhile I noticed small leaks from the side of one manifold spraying water on the valve cover. I replace the manifold only to discover that the exhaut manifolds in the 502 had factory plastic plugs on the engine side of the manifold and they had began leaking. The manifold ran hotter than the raw water system. My Sanjan installation manual said to replace them but I did not since it required maifold removal. I have since bought new manifolds and the newer mercruiser does not have the side plugs. Not sure if a 350 has the plasic plugs. You can see them if it has them.
My boats live in salt water so I install a fresh water system before I put a boat in the water. It is a big job though!

[Zackattack]

Good to know, that is the first I have heard of the plastic insert. I do not think mine has them but I will search for them, so they are on the inside of the manifold just below the riser somewhere?

I do not remember seeing anything else drilled into the manifold except the ports that got used.

Yeah, I thought I was up for just a couple afternoons worth of hose connections and mounting the tank. Wrong, I have at least 15 hours into it.

[harrisdm]

Attached is a picture of the manifold with the plastic/fiber plugs. The plugs are next to the exhaust ports between 1 &3 and 5 & 7. In the picture one plug is still in the manifold (star head plug). The other plug is removed (pipe threads showing).
Another problem I found was length of the zinc anode which is in the plug in the bottom of the heat-exchanger is shorter than most available 1/2" pencil zincs. But you don't know that until the next time you replace it and it is broken-off. The max length on my exchanger plug had to be
1 3/8". So I bought standard 1/2" dia. pencil zincs (Apox 2" @West Marine) and cut it off to the required 1 3/8".
I have installed five of them on different boats and none were easy. I always find a small leak somewere after everthing is warmed up.
Good luck on your trial run.

[Zackattack]

Thanks for the nice picture. I do not think mine are the same, but I will look tonight.

I did a warm up in the driveway and all was well, no leaks. But I will be looking very intently for the first few hours of actual run time. Cant wait til thats possible. Until then I will get to running temp. a few more times in the driveway.

[Zackattack]

Just an update,,,,,,, DO NOT change your original fuel line from the pump to the carb.

I did with two different professionally made lines and lost 1300 RPMs , so for some reason the factory line is CORRECT and needs to be maintained. You need to create brackets for the cooling system that respect the location and existence of the original fuel line from merc.!


TRUST ME, I could bore you with the details if you like.