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525efi Reversion??
I just completed a stock rebuild of a 525 Mark Boos @Precision Marine done the engine work. The engine has stainless Marine manifolds pressure tested good. Broken in on the Dyno with no issues. Installed in the boat after idling until the thermostat opened we checked the manifolds and found a small amount of water/dampness in the bottom of the exhaust manifolds. The risers are Stainless Marine risers and checked good when tested with water off the engine. Could this be a reversion issue? Any advice would be helpful. https://cimg4.ibsrv.net/gimg/www.off...579254ea6d.jpg
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Sounds like reversion. May not end up being a problem if you used inconnel exhaust valves and try to keep the engine off idle as much as practical. Things other than water leaks that could cause this would be cam incorrectly degreed or an exhaust valve not sealing entirely. I'd run it though and watch for more clues.
BT |
BT, I was thinking the same thing. A couple thoughts, we were running on a hose and the water was cold it could have been condensation as it was very damp air also. I also found a small exhaust leak between the manifold and the riser, according to stainless marine this will cause reversion also. I am going to change the gaskets, use sealant and see how it does. Yes I do have inconel valves, this is my first 525 and I may just be overly cautious. |
Running on the hose or in the water?
If on the hose, is the boat sitting at the same angle as when it sits in the water at idle?? Bow being down slightly could make a difference. Its possible that it could just be some condensation as well. |
Originally Posted by Griff
(Post 4664131)
Running on the hose or in the water?
If on the hose, is the boat sitting at the same angle as when it sits in the water at idle?? Bow being down slightly could make a difference. https://cimg1.ibsrv.net/gimg/www.off...c1ef493aef.jpg |
Originally Posted by Lil Mick
(Post 4664111)
BT, I was thinking the same thing. A couple thoughts, we were running on a hose and the water was cold it could have been condensation as it was very damp air also. I also found a small exhaust leak between the manifold and the riser, according to stainless marine this will cause reversion also. I am going to change the gaskets, use sealant and see how it does. Yes I do have inconel valves, this is my first 525 and I may just be overly cautious. |
The leak will cause reversion not because the water is in the joint but it’s pulling more vacuum through the riser |
How does a leaking riser gasket create more vacuum?
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Originally Posted by blue thunder
(Post 4664153)
How does a leaking riser gasket create more vacuum?
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The exhaust escaping sooner pulls more vacuum up the tailpipe. I had it happening with a leak at riser gasket on stand. Eddie young also told me this was likely the reason and it was. |
I am not sure about the reason why, but that was the feedback from Jerry with Stainless Marine. A leak at the top riser joint will make reversion worse. |
Griff we were on the trailer, I do agree that the angle in the water would make the riser angle steeper and most likely drain better. I plan to run it as soon as the weather cooperates and see how it does. |
With all of the technology available and problems with reversion I’m surprised that water in the exhaust is still a thing. I know that it was the best solution at the time 50 years ago, but there has to be a USCG approved option available by now. |
Update I was able to run the boat today, I put about an hour on it. After running I Idled for about 5 minutes then Pulled the riser, it was dry. Griff. I did notice the boat leans to the back more in the water than on the trailer that could lead to the riser draining slower than in the water too. |
Originally Posted by Lil Mick
(Post 4664922)
Update I was able to run the boat today, I put about an hour on it. After running I Idled for about 5 minutes then Pulled the riser, it was dry. Griff. I did notice the boat leans to the back more in the water than on the trailer that could lead to the riser draining slower than in the water too. I'm thinking of doing this to my 525efi's? thanks |
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