Fresh Water Cooling

[Zinger]

Hello, what a great time at Lake George this weekend and with all that clean water i need a full cooling system for my oo 350 Mag MPI Gen 2 can anyone give me so pointers on this topic. Thanks Jeff

[avanti]

We installed the Mercruiser factory system on our 2000 Classic 18 w/350Mag. I don't think it is what you would call a full system, but it does not let any saltwater into the engine, which I think is the important part. Also with this system you do not have to add a sea water pump. The pump on the drive is sufficent. The cost was around 700 dollars and the installation was easy.

[MOP]

For not much more you can over sized or after market. I know for a fact having worked on the owner of Sendure boat that the OEM systems are marginal, most have only a 10% margin on cooling tube capacity. He told me that was their annuity, over heating is not warrantied. If you do use OEM go up an engine size, BB cooler on a SB. Another point a full system is better not only in the fact that the manifolds last almost indefinitely you also pretty much eliminate the riser gasket possible leaking into the engine with the block off plate a little added insurance.

[Cuda]

I put an aftermarket closed cooling on my 350. It runs right at 160, even in the 90 degree water of August here in Florida.

If you run in fresh water only, I wouldn't bother with it though.

[BigGrizzly]

Zinger, All my boats are Closed cooling systems, andI use antifreeze in the motors. All mine are half systems-exhaust is raw water cooled. I don't need the exhaust because my exhaust are Stainless steel and very high output ie 698hp in a 502 with a supercharger. I have done full systems manytimes before and they are great W.Batman has one on his 22 with a Black Hawk drive and it performes well. MOP your out dated I have worked with Sen-Dur for years. Years ago they in fact made the Merc systems. Sen-Dur infact makes full systems for that engine. You obviously worked on their boat over 10 years ago while their father was still alive. They have moved to FT.Lauderdale Fl, and the three sons run the company now. They still have their origional design engineer Bill Rehour who resides on Long island.

Zinger for your infomation there are many companies that make full systems for that application. There are now new systems out called Full Flow systems, much more efficient and more compact than the old type. Mine on the 502 blower motor is 28 inches long and 4 inches wide, which is 24 pounds lighter and an inch smaller in diameter than the older style one on my 351 Ford Clevland in my 18 foot Corsican. If you look at a 496 merc you will see how small they have become(all 496 are closed cooling). I highly recomend a closed system of either type and overheating is not an issue if a sea strainer is used to protedt the engine from debris. I can say this because I have had the same cooling system on our 1966 16 since 1968 and never have had any problems whatsoever with it or any of my other Donzis or my other boats with closed systems. One point our 16 lives in salt water not fresh water like my Criterion.

[MOP]

Randy you are 100% right, I am guessing early 198? he was running a brandy new 20+ ft 4 Winns. I forget what broke but I fixed and got to BS with him. I told him if I had 10 overheats a month 9 were F/W cooled, thats when he told me about the slim margin.

[Zinger]

Big Griz. Can you give me some numbers and names on some full flow systems ,I found a sytem called orca marine for a thousand seems a little high. Jeff

[Cuda]

Here is where I bought mine. http://www.oceaneastmarine.com/freshwater2.html

People told me the Alpha won't pump enough water through the exchanger, but as I said, ran in 90 degree water with no problems.