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HELP with Cooling system

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mikeeh206

New member
I have a '86 bayliner with

I have a '86 bayliner with a AQ131A motor. Hoping for any suggestion on where to start to find out why the water is not circulating thru the cooling system.Just rebuilt the raw water pump and is pumping into the the sea water filter reservor.but the water is not coming of the lower unit. temperatur gage show running at 180-190F. Does the Themostat and Circulating pump play a role?
 
"The gauge is indicating the c

"The gauge is indicating the correct operating temperature for your engine, so I assume the raw water is circulating trough the heat exchanger and exhaust manifold. It is wasn't, I think your exhaust manifold paint would be burned by now and there would be an awful amount of smoke in the engine compartment.

If the water is reaching the strainer, then it is either going to the bilges due to a loose or blown copper pipe or perforated exhaust pipe (I think you probably would have noticed if that was the case), or the exhaust bellows is blown."
 
"Thank El,
New to Boat.
Raw

"Thank El,
New to Boat.
Raw water pump is what suck the water in. What is the purpose of the Circulation pump? My issue is that what is not coming back out.My concern are the the Exhaust manifold get hot. Does the thermostat control when the water will be coming out of the back?"
 
"Mike, your boat has a closed

"Mike, your boat has a closed cooling system. This means the coolant is circulated through a heat exchanger pretty much in the same way the coolant in a car goes through a radiator. The difference is that the heat exchanger is cooled with raw (sea or lake or river) water rather than with air. The thermostat is on the coolant side so it is not in contact with raw water whatsoever.

Try disconnecting the copper pipe under the exhaust manifold ad see if there is water coming through it when you start the engine. If yes, your next step would be removing the rubber hose connecting the exhaust manifold to the exhaust pipe, then connect a garden hose to the hose where the copper pipe is connected to the exhaust manifold and see if water is coming through the riser part. If there is little water coming or you see the riser choked with scale and rust, my suggestion is that you get a new exhaust manifold. Chemical cleaning seldom works on the long run and you don't know how much material is left in the manifold (if too thin, it will get perforated in no time)."
 
"hey El,

My exhaust bellow

"hey El,

My exhaust bellow has small holes across the bottom of it. Is that normal?? They are new and It doesn't take in any water but if my buddy's mercruiser was like that it would flood the bilge??

just brain busting myself!!thx
rofl.gif
"
 
The exhaust bellows has ONE sm

The exhaust bellows has ONE small hole at the bottom when new (a bit larger than a pinhole) and that is to drain the water from the exhaust when you put the boat on a trailer with the outdrive tilted.
 
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