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Maybe the source of a "milky oil.'

WREKS

Jetboaters Lieutenant
Messages
1,167
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475
Points
167
Location
Port Saint Lucie, Florida
Boat Make
Yamaha
Year
2007
Boat Model
SX
Boat Length
23
I noticed this in the cylinder head of the #1 cylinder. At first I thought I might have forced water past the cooling water pipe o-ring while running on the hose at city water pressure (60#+). Can water get into the oil if it gets into the cylinder head. I am going to try to fill the gap with JB Weld Extreme Heat. Does any body have any suggestions?
 

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  • Port Engine cylinder 1 head erosion.jpg
    Port Engine cylinder 1 head erosion.jpg
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That does not look good, I would think you would of had low compression in that cylinder and if anything you would be pressurizing the cooling system. Is there rust on all the valves or just that one cylinder?
 
I doubt any epoxy would work. That is the compression side of the head.
Looks very bad
 
Port engine cylinder head sediment buildup.jpgHere is a bigger view. JB Weld Extreme Heat in not an epoxy; it is more like a water based (I think) hardening sealant. I am able to remove and install the engines now rather easily, so I thought I would give it a shot. Whatever caused that erosion ( I think it was salt) it appears that it eroded from a cooling water passage toward the cylinder head. As you can see, half of the water passageways are plugged up.
 
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Have it tig welded and machined flat again.
 
Have it tig welded and machined flat again.
Thanks for the response Sbrown. Do you have ideas on how it got that way in the first place?
 
@WREKS You obviously boat in salt water. Do you flush with anything after each trip?
 
@WREKS You obviously boat in salt water. Do you flush with anything after each trip?
Thanks for the response Gym. Yes, at least 10 minutes.
 
Thanks for the response Sbrown. Do you have ideas on how it got that way in the first place?
Hard to tell. The casting looks a bit porous in that area, so it may have been due to erosion from combustion gases pushing out. The failure is right under the fire ring, so looking at the headgasket and block in that area may yield additional clues. All just guesswork on my part. I really doubt that would have put much, if any, water in your oil.
 
Hard to tell. The casting looks a bit porous in that area, so it may have been due to erosion from combustion gases pushing out. The failure is right under the fire ring, so looking at the headgasket and block in that area may yield additional clues. All just guesswork on my part. I really doubt that would have put much, if any, water in your oil.
At the beginning of the thread, I mentioned that I had run the engine on the hose at city pressure which is considerably higher than the 25psi that buckbuck had determined for WOT in an experiment that he had conducted. I thought , perhaps I forced water into the area below the valve cover. Is that a possibility?
 
Happens all the time on jet ski heads on Long Island. Welder fills it in and it is machined back smooth. My buddy fixes 3 a week.
Thanks for the reply, Liveto99. Do you know what causes this condition? I hope to avoid it in the future.
 
I will ha e breakfast with Kenny at 6:00 tomorrow morning I’ll see what knows he is the one who fixes them. I believe salt eating them out.
 
I thought , perhaps I forced water into the area below the valve cover. Is that a possibility?
Anything is a possibility, I guess, but it's not likely. There's really no straight path to the oil system from there. I'll be as interested as anybody to see how water got in your oil. I couldn't even venture a guess at this point.
 
Anything is a possibility, I guess, but it's not likely. There's really no straight path to the oil system from there. I'll be as interested as anybody to see how water got in your oil. I couldn't even venture a guess at this point.
I ran it on the hose at city water pressure. May have bypassed o-ring on cooling water pipe.
 
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I ran it on the hose at city water pressure. May have bypassed o-ring on cooling water pipe.
Judged by the pisser action I see when running fast, I would say cooling water pressure at WOT is significantly higher than cooling water pressure when connected to a municipal water supply... anywhere.

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I was going according to Buckbuck's experiment in "Cooling Water Pressures. My city water pressure is 80 PSI. His WOT pressure at the flush connection was between 26 and 27 PSI. But then according to his post-experiment comments there is a pressure drop because of water going to the exhaust and a little to the pilot. And his city pressure is also 80 PSI.
 
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Fills in the void with the tig then they use a belt sander to smooth it back out most of the time. salt eats the heck out of them if they do not flush them out. From Kenny.
 
Thanks Liveto99. I flushed all the time.
 
I was going according to Buckbuck's experiment in "Cooling Water Pressures. My city water pressure is 80 PSI. His WOT pressure at the flush connection was between 26 and 27 PSI. But then according to his post-experiment comments there is a pressure drop because of water going to the exhaust and a little to the pilot. And his city pressure is also 80 PSI.
I was trying to word it carefully, as "cooling water pressure when connected to a municipal water supply".
To my very simple mind stronger pisser stream indicates higher cooling water pressure in the system. That stream is always significantly "stronger" when running at WOT as compared to running on a hose.

Sorry, I forgot now the exact reason for those statements but in general I would think you have salt (aluminum oxide) build up in your cooling passages restricting cooling water circulation that over time created enough obstruction to cause secondary issues.
(Chemically speaking, most salt compounds are not water soluble, or barely, and do not taste like kitchen "salt", btw.)

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