Cooling question


rpm605

rpm605

Member
Boat is 2002 37PC with twin Bravo 3's and 8.1 mercs. Do he intakes on the bravo 3 drives provide any cooling for the engines or are they strictly for the drives?

Engines are fresh water cooled, but didn't know if the intakes on the drives circulated through the engines at all or just the drives.
 
Raw water that is picked up from the drive is pumped through heat exchangers on the engine to cool them. Think of the exchangers like radiators on a car, instead of liquid to air on a car, they are liquid to liquid on a boat. The water picked up from the drives to do this does nothing to cool the drives, there are external drives showers the handle this if needed.
 
afratki said:
Raw water that is picked up from the drive is pumped through heat exchangers on the engine to cool them. Think of the exchangers like radiators on a car, instead of liquid to air on a car, they are liquid to liquid on a boat. The water picked up from the drives to do this does nothing to cool the drives, there are external drives showers the handle this if needed.
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Then what about the water that gets drawn in through the sea water intakes with the big strainers? Do the engines get cooled with both?
 
Someone correct me if I'm wrong as I don't have this model boat but the two sea strainers are probably for the generator and A/C pickups. Someone could have added strainers if you are certain they go to the heat exchangers because I don't believe they came from the factory with them. Either way, the engine is definitely cooled from the water picked up by the drive, it's the most consistent and reliable source of water.
 
Boat can be built with external seawater pickups (thru hulls) and strainers or by using the drives as the intake. So just because you have B3 drives does not mean they are being used to draw water in. Take a pic and post so we can see what you have
 
HVAC has it's own seawater pickup, generator has its own seawater pickup and each engine has it's own seawater pickup. All have their own strainer systems and none are interconnected.
 
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Post a picture of your setup.

If you look behind your motors you will either see a hose attached to the inner transom assy running under the STBD side of your motor, OR you will see a block off plate there attached with 2 bolts. Someone could have blocked them off and switched over to thru-hull pickups and strainers. I'm actually thinking of doing this same thing....hence why pictures of your setup would be great.....so I can see where the strainers are mounted, and thru-hull's were drilled.
 
I will take some photos, but it won't be until next weekend. Thanks for the replies so far.
 
AllDodge said:
Boat can be built with external seawater pickups (thru hulls) and strainers or by using the drives as the intake. So just because you have B3 drives does not mean they are being used to draw water in. Take a pic and post so we can see what you have
Click to expand...

I guess PC's are different, learned something new. Most of my experience is around performance boats that would never be set up this way, the hull spends too much time out of the water :rolleyes:
 
Here is a shot of the water intake line coming through the transom. It's cut, plugged and clamped. Same on both drives. So I guess no water coming through for engine cooling

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And here is the sea-water intake and strainer. Note the block of wood used for support for the seacock. If this were done at the factory, I would guess the reinforcement material would have been glassed in. Guess it's safe to say all this was done after purchase. Is there any chance the factory would have done this?


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Yes this was an after the fact install, looks good for the strainer install. So long as you don't have any overheat issues it was probably installed correctly.

Don't really like the hose an plug, would prefer using the block off plate on the transom assembly. Hope they did either remove or cut the feed hose on the outside.
 
thanks for the pics. definitely not a factory job, but looks like a relatively clean install. they do sell a block off plate for the transom assy, but the problem is getting to it. That's more than likely the reason yours is plugged.
 
No issue with overheating. Leaving things alone. They are working fine, no sense in taking a chance. Very sad today, just finished my winterizing. Counting the days until March.
 
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