Closed (fresh water) cooling- Why don't all engines have it?
 

Sorry if this is a stoopid question but as a guy who plays in salt water, I just don't know why all boats don't have it?
(If you don't laugh me off the forum, I've got a couple more stoopid questions I might post)

There's no argument that salt water boats require a bit more attention to keep them perfect and fresh water cooling is an advantage with preventative maintenance but aside from the initial cost, I just don't get it.

Does FWC suck horsepower?
Does it use extra fuel?
Does it take up too much space?
Does it require additional maintenance?
Does it not work on high performance engines?

I would think "Not really" to all of the above so what is the reason it's not standard right across the range?

RR

I too would like to know. Even in fresh water boats FWC has serious advantages. With the amount of money spent on engines it would seem like a no brainer.

I would think for the same reason not all motors use forged cranks and pistons. MONEY!!!! Mfrs will go to great lengths to save a penny anywhere they can.

Not a stupid question. Cost, weight, complexity and packaging are reasons not to offer it. Big power would take a really big heat exchanger. I have used it before and liked it.

FWC is the best insurance you have along with guardian mode. They have saved my motor and headers countless times !!!!!!!!

I've just had a good read through mercuryracing.com and it seems the blue motors now have closed cooling which means it must be a good thing!

Even the 1650 reads "Engine and turbocharger center sections are closed cooled............." This answers my initial question for the bigger engines but the average boater with his small block V-8 or a V-6 would really benefit from the little extra option.

I suppose as CrownHawg said, it's just penny pinching by the manufacturer.
I hope all the raw water cooled engines corrode and blow up and Mercury can spend a whole lot more rebuilding them under warranty!

RR

Some of the most expensive items on the engine package would be negatively impacted- the exhaust and intercooler. The intercooler wants the coolest water possible and water that's been through the heat exchanger (hx) will never be as cool as the raw water stream feeding it. The exhaust just wants all the water it can get, it's a rather large hx to fill, and thus would require an much larger primary hx to cool the stream before reentry to the block. This could of course be made to work, at the expense of space.

No system additions come without penalty, and one can fairly easily mitigate the corrosion issues on a pleasure boat so why add the complexity?

I think it is the Customer who goes through great lengths to save a penny anywhere they can, If it was THAT important to have it than any motor with out it by this time will have become obsolete.

I look at it this way. I consider exhaust to be a wear item on a marine engine so I am installing 1/2 systems on my motors. This way my engine is protected by antifreeze, the heat exchangers are a manageable size, and plumbing is simple. fresh water pickup>sea strainer> raw water pump>heat exchanger>Manifolds>risers. The engine with its circulating pump just connects to the heat exchanger. Easy to winterize, expensive engine protected all year round by antifreeze.

Sounds like a merc or Illmore LOL