Omc Fresh Water(closed) Cooling System ??

[fourwinns88]

I have an 88' Four Winns 200 Horizon w/4.3L,Cobra outdrive. I am more familiar with automobiles so my question is this: Would the engine run warmer with a closed cooling system due to the fact that there is not a fan to cool the coolant as it leaves and re-enters the engine or should it still run the same temp as a raw water cooling system. I am a little baffled on how the coolant is "cooled" without the use of a fan as on a car engine. The reason I ask is that it will run approx. 190 degrees all day (goes down to about 175 when in a no-wake zone). I replaced the impellar and and thermostat(160) and no change. Is this operating temp. OK? Any help would be greatly appreciated.

 

[180shabah]

Re: Omc Fresh Water(closed) Cooling System ??

If you have a closed cooling system, then you have a heat exchanger as part of the setup. Engine coolant on one side - lake/river water on the otherside.

Your temp should be very stable witha closed system. How old is the impeller in the seawater pump, it should be replaced every year or at least every other year in good clean water.

 

[180shabah]

Re: Omc Fresh Water(closed) Cooling System ??

Forgot the exhaust side. Do you have a full system(also run the coolant through the manifolds) or a half system(coolant only runs through the bolck)?

In salt water, you exhaust components only have a life span of about 5 years. When the risers start to clog, they will restrict waterflow on the seawater side of the system.

 

[futz]

Re: Omc Fresh Water(closed) Cooling System ??

what do you have, see 190 is right on the border, if you have closed then clean out any heat exchanger. power steering, has a heat exchanger also.

Ether raw water, or closed if you have a riser clogged then you will have a high heat condition.

Maybe a flapper / shutter fell down the exhaust and clogging you up.

Engine mounted recirculating water pump good?

 

[bruceb58]

Re: Omc Fresh Water(closed) Cooling System ??

Is your closed cooling system aftermarket? Some of those systems had marginally sized heat exchangers so you may be at the limit of what the heat exchanger will work with. What temp water are you running in?

 

[fourwinns88]

Re: Omc Fresh Water(closed) Cooling System ??

Thanks for the responses. I think it runs coolant through the risers as well because there are rubber hoses on the fronts of each. What does the heat exchanger look like? Is it the canister that holds the coolant? Also, the water temp is somewhere around 80 degrees. The seawater impellar is two months old (only ran one time since replaced). I hope this helps. Thanks again for any additional comments/suggestions.

 

[HT32BSX115]

Re: Omc Fresh Water(closed) Cooling System ??

I am a little baffled on how the coolant is "cooled" without the use of a fan as on a car engine.

Howdy,

If you truly have "closed cooling" and the engine is full of 50/50 glycol,

Think of the raw water pump in your drive as the "FAN"

Then think of the heat exchanger as the radiator and the air thru the radiator being the "Lake" water.

Also, depending on if it's a full system or a half system, the "Lake Water" exits the heat exchanger and is directed thru the manifolds and risers (half sys) or the risers ONLY (full system)


It's VERY EFFECTIVE because water as a heat transfer medium is FAR better than air and you have a unlimited supply in the water below your boat.

My 454 full closed system runs at about 160*F in 80* water. If you want to know more about these systems, here's a good description http://www.boatpartsinfo.com/cooling-systems.html

And here's a great description of common problems.. http://www.boatfix.com/how/cooling.html



Cheers,

Rick

 

[fourwinns88]

Re: Omc Fresh Water(closed) Cooling System ??

Thanks again. One last thing, would 190 be an unacceptable temp at least for the remainder of the season(it never exceeds that)? I have a full winter ahead to correct any problems.

 

[HT32BSX115]

Re: Omc Fresh Water(closed) Cooling System ??

You'll get varying opinions here probably.....hot running at high power settings is frequently due to blockage (previous impeller fragments in the heat exchanger, oil cooler, PS cooler, main heat exchanger, etc) or someplace else in the raw water circuit like plugged risers/elbows (see the links I provided)

190 isn't going to break anything (assuming your gage is actually right) It will probably get worse though as it gets more "plugged" up.

I would want to fix it soon.


You mileage may vary...

 

[bruceb58]

Re: Omc Fresh Water(closed) Cooling System ??

Also, the water temp is somewhere around 80 degrees.

According to the people at San Juan Engineering, 80 degrees is on the warmer side for their exchangers to be able to work effectively. I know when I had spoken to them, they said I might have problems when I went to warmer lakes that had water approaching that temperature.

 

[HT32BSX115]

Re: Omc Fresh Water(closed) Cooling System ??

According to the people at San Juan Engineering, 80 degrees is on the warmer side for their exchangers to be able to work effectively. I know when I had spoken to them, they said I might have problems when I went to warmer lakes that had water approaching that temperature.

I just got back from running my 454/Bravo (with a San Juan Engr full sys) at Lake Oroville (80*), Lake Englebright (70-80*) and Tahoe. (well....Tahoe was a bit cooler!!!.....Well a LOT cooler!but in places up to 70*F )
I measured temps with my new Lowrance HDS5 and skimmer sonar sensor.

Anyway, at 80* the regulated temp didn't change much....pretty much stayed at around 160-170...... Now I am using Bravo with drive water pick-up. Bravo's have VERY good raw water flow even from the drive.

I was worried because San Juan told me the same thing when I got mine....I thought I might have to go to a separate raw water pickup in the bottom of the hull...


The Cobras have pretty good flow too.

There is a guy locally here that had a problem with his Alpha not providing enough flow for his closed system (in pretty cold water: Puget Sound)

He did get it to work though......I think his was a plumbing problem....

 

[fourwinns88]

Re: Omc Fresh Water(closed) Cooling System ??

I appreciate all of the input. I printed off the links and they should be very helpful. This is a great website and all that participate with helpful hints and information for the, well, lack of boat knowledge folks like myself, are thankful. Thanks to all