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Path of H2O through the engine?


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Just got through putting my baby to bed for the winter. Cry.gif While I was warming up the engine hoked up to a hose I was wondering how the water flows through the engine. After it goes throught the tranny cooler I think it goes to the tstat. But then where? If I recall, doesnt the monsoon have a bypass that routes water to the manifolds until the block warms up and needs cooling?

Just got me wondering and I figured someone here would probably know.

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The water flow is typically Lake > Trans Cooler > RW Pump > Tstat Housing > Manifolds > Out through exhaust. Only when the Tstat opens does water go into the block/circ pump.

This is why the old "if the AF comes out the exhaust you are good to go" addage is incorrect for winterization.

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The water flow is typically Lake > Trans Cooler > RW Pump > Tstat Housing > Manifolds > Out through exhaust. Only when the Tstat opens does water go into the block/circ pump.

Correct, (except) the water comes from the water pump, then into the block, then through the tstat, and out through the exhaust. The tstat holds/restricts the water flow in the block, once the block is up to temp, it regulates the flow to maintain the temp (I wasn't sure if that is what you meant by block/circ pump).

I attached a pic of mine with some very rough arrows on it.

post-144-1131320357_thumb.jpg

Edited by Sunsetter95
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My trans cooler is after the rw pump, and I think it is in your picture too (except I can't see your rw pump). The bypass takes place in the t-stat housing. I agree with what sunsetter 95 said. The water out of the rw pump is diverted in the t-stat housing to two places - the exhaust manifolds (bypass) and to the engine cooling pump. So say if the block were empty, it would immediately fill with water, but would not exit the engine until the t-stat opens. And with the stat closed, essentially all incoming water goes through the bypass and out the exhaust. Once the stat opens, then you have water flowing through both loops, since from what I can see the bypass doesn't get closed off when the stat opens. But due to the hose sizes, I think most of the water will go through the engine. The water that exits the engine out of the intake manifold will take the same path as the bypass water into the exhaust manifolds and out the exhaust. The monsoon is slightly different from the above picture, but not far off.

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How about in a "closed-cooling" system? With a V-drive?

I think raw water only touches the V-drive, transmission raw water pump, heat exchanger and manifolds/exhaust... I don't know for sure though...

JZ

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I was wondering this myself while running the boat in the carport and noticing a drip from the water pump, which I guess means I need to order another from SkiDIM and replace over the winter? On my Monsoon it comes up the intake, through the impeller, to the tranny cooler, then I guess onto the water pump? Is a water pump and circ. pump the same thing? How far does the impeller push the water and where does the water pump take over?

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So say if the block were empty, it would immediately fill with water, but would not exit the engine until the t-stat opens.  And with the stat closed, essentially all incoming water goes through the bypass and out the exhaust.

I think you've got it. I just winterized this weekend and I should have tested this on a cold engine. All you'd have to do is drain the block, then run it for a minute and try to drain the block again.

I only used 2 gallons of antifreeze on a warm, empty block, exhaust manifolds and heater. I drained the antifreeze afterwards and it was everywhere it needed to be.

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Yeah, I didn't even think about it until now, but for those that drain everything, and then pour antifreeze into the engine with it running, there really is no need to worry about the stat being open vs. closed.

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I winterized my Monsoon 320 this weekend I emptied the water from the block by removing the petcock and knock sensor from the sides of the block and also the drain plugs from the rear of the exhaust manifolds. After replacing these items, I disconnected the inlet hose at the fitting in the hull and then poured Anti-freeze with a funnel down the hose as fast as the raw water pump would consume it.

I used 4 gallons of antifreeze before any came out the exhaust pipes in the transom. I would guess that it filled up the block first since the volume of the hose is much less than 4 gallons.

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HR, dont let that drip go too long, or u'll be replacing the housing as well!

Yeah, I intend to do it soon, I guess when I winterize. It appears to be dripping from behind the pulley, best I can tell, but as Jack can attest, I may as well be looking at a Dixie® cup as trying to diagnose a water pump problem. Where is the weep hole supposed to be, if it has one?

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There is a weep hole behind the pulley next to the shaft of the circulating pump. Water dripping from there means that the seals are going. I had the same problem a couple of years ago. Got a replacement from SkiDim & replaced it easily.

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HR, dont let that drip go too long, or u'll be replacing the housing as well!

Yeah, I intend to do it soon, I guess when I winterize. It appears to be dripping from behind the pulley, best I can tell, but as Jack can attest, I may as well be looking at a Dixie® cup as trying to diagnose a water pump problem. Where is the weep hole supposed to be, if it has one?

Correct, the drip is coming from a vent hole in the WP housing which is indicating that the WP seal is bad.

You cannot see my RW pump in my pic but correct, inlet->RW pump->trans cooler->tstat housing and bypasses->WP....

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