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Uneven exhaust flow

kghost said:
These are the two images from my manuals.

left image is for 454

right one is from a V6 manual. The sleeve does not show the cut outs but I added it for comparison of the over all assembly.

It is obvious by the photo that the sleeve is ON TOP. Note the orientation of the cut outs in the sleeve. They point towards the engine block at ~ 10:00 and 2:00 o'clock
The only issue is the circular gasket. One image shows it below and the other above.

I am not sure it matters as the height of the sleeve will be the same.

I would say go by the image on the left!

Been a while since i have physically been inside one.

Also the image of the thermostat itself is the original OEM type. Mine lasted almost 30 years and finally failed.
Click to expand...

interesting, every time I’ve seen one the thermostat is sitting on top of the sleeve directly under the top cap. That’s why I wasn’t sure if I should follow the diagrams I was seeing online.

I will replace lace how I see it here.
 
If you think about it,
The sleeve with the cut out in it, the cut outs should be inline with the water ports.........

The thermostat sits deep down in the housing correct?

So when it opens the water is diverted thru the sleeve to the ports.

Make sense?
 
The sleeve I have does not have cut outs, just a brass ring with a lip on one side. Regardless it makes sense what your saying. I’ve just seen a few where the thermostat is sitting on top of the sleeve. So when I looked into it I was confused. Thanks though
 
Looks like you have old design

Look here for both, Old design and new design

New design the output ports are in the housing

Old design the output ports are in the cap. Thus the sleeve with no cut outs


New design
http://www.marineengine.com/parts/m...4-thru-0b785148/thermostat-housing-new-design

Old design
http://www.marineengine.com/parts/m...4-thru-0b785148/thermostat-housing-old-design


Having the thermostat on top of the sleeve is most like;y the cause of your issues now that the hoses are routed correctly
 
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kghost said:
Looks like you have old design

Having the thermostat on top of the sleeve is most like;y the cause of your issues now that the hoses are routed correctly
Click to expand...

Yea I do and no that makes perfect sense. Someone obviously did some work on this and reassembled the thermostat housing the wrong way. I just always assumed it was supposed to sit on top like it was.

Thanks again man, really appreciate you.
 
Please note:

There is no additional SPEW needed from the one and only.

Case closed!

If he had a clue he would have resolved this but as usual only useless second hand "advice" not worth a crap!
 
mcomm said:
Nice work Jack
Click to expand...

Thanks but it was not all me or anything of the sort.
The OP just had things the wrong way.

What is true, is all my unrelated babble over Dicardo............If you notice he rarely if ever has a path to follow to solve a problem.

He simply posts spew and tries to make everyone who is "uninformed" think he knows what he's talking about.

He may have "some" knowledge of Volvo but he certainly has ZERO knowledge of Mercruiser. There in no doubt of that!

He tries to take the Volvo stuff and attempt to apply it here when is does not.

His post here simply add to the confusion of the OP. Nothing fact or experience based. Simply copy and paste from who knows what source.

He has no manuals, no working knowledge of the product No F'N clue!

Done, Peace, out!
 
kghost said:
Thanks but it was not all me or anything of the sort.
The OP just had things the wrong way.

What is true, is all my unrelated babble over Dicardo............If you notice he rarely if ever has a path to follow to solve a problem.

He simply posts spew and tries to make everyone who is "uninformed" think he knows what he's talking about.

He may have "some" knowledge of Volvo but he certainly has ZERO knowledge of Mercruiser. There in no doubt of that!

He tries to take the Volvo stuff and attempt to apply it here when is does not.

His post here simply add to the confusion of the OP. Nothing fact or experience based. Simply copy and paste from who knows what source.

He has no manuals, no working knowledge of the product No F'N clue!

Done, Peace, out!
Click to expand...

i hate to say it but we’re still having temperature problems over here. Today I decided to get a true temp reading. Fired up the boat, let it warm up and then ran it for 5 mins at idle with the drive lowered into a tub with plenty of water coming in through the hose to drink.

We got well over 200 degrees at the gauge after about 4 mins. The starboard side elbow is fine, but the port side elbow is getting HOT. And I mean HOT. it started steaming something awful. I also noticed the thermostat cap was also very hot.

Plenty of water return from both exhausts, nice and even. It’s just the port side that’s getting hot. What in the heck is going on here?!

Ive literally checked everything!
 
One side that hot would suggest no flow either in or out or a obstruction or stuck thermostat..
What thermostat?
Remove and retest.

Post some freaking pictures of ur thermostat housing.

You have done something wrong or missed something!

You also may want to disconnect the incoming hose as you did before and see how much water is being DRAWN in.

It should fill the bilge fairly quickly.

As an alpha one gen I, it is high pressure low volume system.
Gen II is low pressure high volume.
 
kghost said:
One side that hot would suggest no flow either in or out or a obstruction or stuck thermostat..
What thermostat?
Remove and retest.

Post some freaking pictures of ur thermostat housing.

You have done something wrong or missed something!

You also may want to disconnect the incoming hose as you did before and see how much water is being DRAWN in.

It should fill the bilge fairly quickly.

As an alpha one gen I, it is high pressure low volume system.
Gen II is low pressure high volume.
Click to expand...

Got a 140* thermostat. Are you suggesting I remove the thermostat and run the boat without it or test the thermostat itself on the stove?

there is a good amount of water coming in with the hose disconnected before the oil cooler and still a good amount after the oil cooler.
 
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The thing I don’t understand is I have even water return and plenty of it out the exhaust. Yet one manifold, riser and elbow is hotter then the other.. while the port side is getting HOT the starboard side is just warm.

I noticed the thermostat cap was also very hot which leads me to believe the water is HOT before it gets to the thermostat housing. Is there anyway there could be a blockage within the water path internally inside the block? If so what could cause this? Is there a way to flush these passages out?

High pressure water alter or air maybe?

Im honestly starting to think this is more then a flow issue.
 
The thing I don’t understand is I have even water return and plenty of it out the exhaust. Yet one manifold, riser and elbow is hotter then the other..

I noticed the thermostat cap was also very hot which leads me to believe the water is HOT before it gets to the thermostat housing coming out of the engine.. Is there anyway there could be a blockage within the water path internally inside the block?

If so what could cause this? Is there a way to flush these water passages out? High pressure water or air maybe?

Maybe the circulating pump pump is bad/ defective?

makes no sense, how can hot water at the thermostat housing cool one side but not the other?
 
EDIT...

The thing I don’t understand is I have even water return and plenty of it out the exhaust. Yet one manifold, riser and elbow is hotter then the other..

I noticed the thermostat cap was also very hot which leads me to believe the water is HOT before it gets to the thermostat housing coming out of the engine.. Is there anyway there could be a blockage within the water path internally inside the block?

If so what could cause this? Is there a way to flush these water passages out? High pressure water or air maybe?

Maybe the circulating pump pump is bad/ defective?

makes no sense, how can hot water at the thermostat housing cool one side but not the other?
 
The only thing I can suggest is you are getting exhaust in the incoming water.
Exhaust comes out of the prop and into your bucket which is in turn being drawn in.

Try it on the ear muffs alone
 
kghost said:
The only thing I can suggest is you are getting exhaust in the incoming water.
Exhaust comes out of the prop and into your bucket which is in turn being drawn in.

Try it on the ear muffs alone
Click to expand...

The boat has through hull exhaust..

i called a mobile mechanic that I’ve used in the past he’s going to come take a look at it tomorrow.

you don’t see any point in replacing the circulating pump?
 
Can only do so much through a web site,


Your missing something, a piece of scale or the thermostat is bad or something between the water pump impeller and thermo housing is restricting flow,

Engine water pumps (circulating) rarely if ever go bad. they have by directional BRONZE impellers.

PM me your phone number
 
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