Mercury FOURSTROKE: Lubricating Oil Contamination With Cooling Water

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Author Topic:   Mercury FOURSTROKE: Lubricating Oil Contamination With Cooling Water

Stephen_12 posted 08-01-2012 07:00 PM ET (US)
[This article was appended to a four-year-old discussion. Please do not revive four-year-old threads. This advice still applies--jimh]
My 2005 Mercury 90 HP is getting salt water in the oil. [Although not clear, I and several other readers believed he meant that the gear case lubricant was becoming contaminated with water. However, later--much later and among several different threads, now combined into this single thread--we find out that the problem being described is the presence of cooling water, in this case saltwater, in the lubricating oil of the engine--jimh] Compression is 105 to 110-PSI when cold on all cylinders. It runs greatly with plenty of power, [and the] spark plugs all appear normal tan color with no rust. I get about about four-ounces of water every 25-hours of use. I drain it after the engine sits by loosening the drain plug and letting the water out until I get clean oil. Seems to be working but I'd like to know where it's coming from.

sosmerc posted 08-07-2012 08:41 PM ET (US)
I just finished working on a 2003 60-HP Mercury FourStroke and I actually found a hole eaten through the exhaust adapter plate on the port side. It was blowing exhaust out the hole. The hole was below the cowl seal, so I don't think it was getting back into the intake causing a problem. The engine was in for fuel related repairs--very dirty filters and a dirty VST tank. I plugged the hole with Marinetex and water tested the boat today. The engine is running fine, but I am VERY concerned about what other corrosion damage there may be in that adapter plate. Could corrosion in just the right spot allow cooling water (saltwater) to enter the crankcase oil reservoir? Is that what is occurring with the fellow in this thread. [YES--jimh] My understanding is that these power heads are coming from overseas and they are then assembled in the US. Maybe their metal is inferior to what Mercury has been using in their domestic produced engines. I wish Mercury would get back to designing and building all their own stuff here at home.
L H G posted 08-08-2012 07:44 PM ET (US)
From what I understand 2003 was the first year of the 60 4-stroke and it was 100% Fond du Lac manufactured, with larger displacement. [Gave his version of a short history of collaboration of Yamaha and Mercury on making engines.]
sosmerc posted 08-08-2012 09:54 PM ET (US)
The 2003 60hp Mercury engine that I was referring to stated on the serial tag: "Assembled in the USA with both foreign and us parts." The thermostat cover had the baked on black coating that totally resists any salt buildup, but the water passages behind the cover had no apparent coating and there was a lot of salt buildup. If ALL of the water passages had this black coating we would never experience any corrosion issues.
Stephen_12 posted 08-11-2012 09:38 AM ET (US)
My 2005 Mercury is getting water in the oil. [This ambiguous mention of oil again prompted more inquires about which oil was being referred to.] [Finally Stephen tells us he means] the crankcase oil. I have torn down [the 2005 Mercury 90-HP FOURSTROKE outboard engine] now. I'm not seeing any problems with the head gasket. [The engine cooling water] may have been leaking from the water tube grommet into the oil sump. [Emphasis added--jimh.]
I will re-assemble [the 2005 Mercury 90-HP engine] this weekend and will perform a pressure test of the cooling system to see if it has any other leaks.
Seems like most people with this problem write it off to condensation but my engine was leaking saltwater into the oil. For those who have offerred to help, much thanks. When I get this sorted out, there will be more pictures.

Stephen_12 posted 08-11-2012 05:52 AM ET (US)
[I have deleted several other threads that STEPHEN-12 started that discussed this problem and have apppended them to this thread. So now, finally, we have Stephen's discussion about his problems with his Mercury FOURSTROKE all in one thread and in the proper place. It has been about an hour's work to move all this around and get it into one place, but here we finally have the story, even if it is a bit disjointed and repetitious--jimh]
I had been enjoying the smooth quiet power of my 2005 Mercury 90 HP four stroke when I happened to read all about the water in oil problems many were having. I changed my oil this Spring and about 1 cup of water and sludge came out. After flushing the engine with new oil, I read that these engines have to be run hard and that the thermostat has to be changed. Checking the thermostat revealed that it was stuck wide open so I replaces it and felt like I had done something good only to find that the engine oil was contaminated with water after only 2 trips on the boat. So I drained the oil and sampled the water that came out and found it to be salt water. Then I visited by local dealer who told me that the problem was pretty common and that it usually was due to a corroded adapter plate underneath the powerhead. So now I have the entire engine disassembled and don't see any problems with the adapter plate or gaskets in that area.
I had checked compression and it was 110, 110, 105, 105. The engine runs very smooth and it will rev to 6000 RPM with an 18" prop on my Boston Whaler Montauk 170.
Today I will disassemble the entire powerhead and look for cracks, corrosion, or a blown gasket.
My friend at work has the same boat with a Honda 75 HP and we spoke and he found water in his oil. He pulled his engine apart and found a blown head gasket. He had low compression so it makes more sense than mine.
Any suggestions?
Stephen_12 posted 08-11-2012 07:39 PM ET (US)
I'll figure this out. But so far, no real clues as to where the water is coming from. The head gasket wasn't blown; the sump is like brand new; and the exhaust adapter plate and gasket looked pretty good.
The head gasket comes apart in three pieces so it's hard to see what condition it was in before I removed it. There is no evidence of water entering any of the cyclinders and there is no rust or evidence of "steam cleaned" pistions. They all looked the same with a light carbon coating.
The only thing I can find that's even slightly questionable is the water tube grommet where it connects to the adapter (exhaust) plate. If that thing leaks, the water will go into the oil sump. The grommet looked like it may have been weeping. [Emphasis added--jimh.]
I cleaned up all the parts, checked the block and head for warping (they are within .001 inch each so that's not it, and await all the new seals and gaskets. I noted that Mercury superseded the part numbers for some of these items so there may be more to the story. Maybe the problem is that the seals and gaskets were no good from day one.

Jefecinco posted 08-11-2012 07:48 PM ET (US)
There have been cases of engines getting water in the crankcase when the engines have been mounted too low on the transom.
I don't pretend to know how it happens but when a boat is abruptly slowed from on-plane speed it creates a large backwash which sometimes splashes water into the motorwell. If the engine is mounted low the backwash could come pretty high on the engine cowling. Some water could get under the cowling and find it's way into the crankcase.
Pretty farfetched but perhaps worth your consideration.
Butch
Stephen_12 posted 08-11-2012 07:53 PM ET (US)
Here are some pictures of the engine:
PIC1
PIC2
PIC3
PIC4
PIC5
[Note: there are many more pictures of the engine (without any captions) on the hosting side in that album.--jimh]
contender posted 08-11-2012 09:04 PM ET (US)
If you can not find a bad gasket then you have a crack somewhere, One day after the salt has set on one of your bearing the engine will stop--permanently
sosmerc posted 08-14-2012 11:15 AM ET (US)
Be sure to check the thermostat. If it's stuck open your engine will run too cold and this can cause a 4 stroke to "make oil". Actually it's adding condensation to the crankcase, and because the engine doesn't get up to proper temp the condensation fails to boil off. Also, the engine will run too rich because of improper temp.
jimh posted 08-14-2012 08:13 PM ET (US)
I finally found all the places where Stephen was posting about this problem and joined them to one thread.
Stephen_12 posted 08-18-2012 11:35 PM ET (US)
For those that wanted to know how I determined that the water in my oil was salt water, I loosened the drain plug and out came about 4 ounces of clear water which I caught in a cup. Then the oil followed. I don't recommend doing this but I tasted [the water] quickly and it was very salty.
Stephen_12 posted 08-18-2012 11:40 PM ET (US)
I am in the process of re-assembling the engine now. I made a jig up so that I could pressure test the block while it is off the mid section. I was able to pressure test the cooling system of the power head once I had the head back on with a new gasket. I brought it up to 20 psi with air and it held quite well so I am confident that I don't have a cracked block or head.
I resealed the adapter plate (exhaust plate) and the oil sump and will try it out next week. Hopefully, it was the water tube o-ring area that was leaking into the sump.
jimh posted 08-19-2012 10:20 AM ET (US)
Stephen--I hope you had a shot of Scotch handy to get the taste of the contaminant out of your mouth. Thanks for the information. I once siphoned some gasoline and started it with suction by mouth; I think I can still taste that gasoline.
Considering the volume of water you found and the tendency for this to be a constantly occurring problem, I agree with your analysis that the path for the water to enter the oil must have been some sort of leak in the cooling system.
The prior discussions mentioning "making oil" in four-cycle outboard engines have all been focused on the oil becoming contaminated with condensation of water vapor or by blow-by of combustion chamber gases into the crankcase. These conditions are often associated with engines that operate at too low temperature due to poor regulation of the cooling. Your situation seems to be more likely to be a leak between the oil path and the cooling path.
Also, kudos for tearing apart this complicated four-cycle outboard engine, and, we hope, putting it all back together. You now probably have greater knowledge of this engine than any reader.
Stephen_12 posted 08-20-2012 07:46 PM ET (US)
For those who have been following this discussion, I completed the re-assembly yesterday and fired up the [2005 Mercury 90-HP FOURSTROKE using a hose adaptor]. It runs great--no difference, it always did--and after one hour of running, I let it sit and cool down and checked my oil. No water! I removed the drain plug and what came out was...OIL!.
Then I ran [the 2005 Mercury 90-HP FOURSTROKE] for another hour using a plastic [water] tank and added cold water constantly to keep the tank cold enough. I sampled the oil, and, once again, no water.
I have to question what Mercury Marine was trying to accomplish by putting the water tube and grommet through the oil sump. It would be a lot less risky if they routed it around the sump, as far away from the oil as possible. But their engineers must like to live on the edge so the water and oil are separated only by a grommet and about 1/4-inch of aluminum. [Emphasis added--jimh]
I don't recall worrying about any of this with my previous Whaler and it's dependable 90 HP Mercury 3-cylinder 2-Cycle.
Well, for now, the plan it to go back to boating and allow this pile of black nuts and bolts to sit on the back and behave itself while it pushes me around in pursuit of stiped bass.
fishforfun2 posted 03-20-2015 03:34 PM ET (US)
[Revived this thread after several years of being dormant. Now expects participants from years ago to reply. Please note that it is not a good plan to expect people to be following a thread they started three years earlier--jimh]
I have the same problem on my [2004 Mercury 115-HP FOURSTROKE]: water in oil every time I change it. Did changing the upper seal #12 part number 814080001 fix the problem or was it a different seal, Stephen? If that's the one, can I change it without removing the powerhead? Just remove lower end and mid section covers? Thanks--Dale
jimh posted 03-21-2015 10:07 AM ET (US)
As this thread was just revived, I have re-worked it to remove all the spurious comments and discussion, and tried to concentrate the information on the topic of contamination of the the lubricating oil of a 2005 Mercury 90-HP FOURSTROKE outboard engine with cooling water, in this case saltwater, that is apparently caused by a leak at a gasket or grommet or O-ring or seal of some sort where a cooling water pasagge in the enging block, in this discussion sometimes called "a tube", passes near to a portion of the block which is part of the oil circulation system, and cooling water can escape into the oil system.

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Author	Topic: Mercury FOURSTROKE: Lubricating Oil Contamination With Cooling Water
Stephen_12	posted 08-01-2012 07:00 PM ET (US) [This article was appended to a four-year-old discussion. Please do not revive four-year-old threads. This advice still applies--jimh] My 2005 Mercury 90 HP is getting salt water in the oil. [Although not clear, I and several other readers believed he meant that the gear case lubricant was becoming contaminated with water. However, later--much later and among several different threads, now combined into this single thread--we find out that the problem being described is the presence of cooling water, in this case saltwater, in the lubricating oil of the engine--jimh] Compression is 105 to 110-PSI when cold on all cylinders. It runs greatly with plenty of power, [and the] spark plugs all appear normal tan color with no rust. I get about about four-ounces of water every 25-hours of use. I drain it after the engine sits by loosening the drain plug and letting the water out until I get clean oil. Seems to be working but I'd like to know where it's coming from.
sosmerc	posted 08-07-2012 08:41 PM ET (US) I just finished working on a 2003 60-HP Mercury FourStroke and I actually found a hole eaten through the exhaust adapter plate on the port side. It was blowing exhaust out the hole. The hole was below the cowl seal, so I don't think it was getting back into the intake causing a problem. The engine was in for fuel related repairs--very dirty filters and a dirty VST tank. I plugged the hole with Marinetex and water tested the boat today. The engine is running fine, but I am VERY concerned about what other corrosion damage there may be in that adapter plate. Could corrosion in just the right spot allow cooling water (saltwater) to enter the crankcase oil reservoir? Is that what is occurring with the fellow in this thread. [YES--jimh] My understanding is that these power heads are coming from overseas and they are then assembled in the US. Maybe their metal is inferior to what Mercury has been using in their domestic produced engines. I wish Mercury would get back to designing and building all their own stuff here at home.
L H G	posted 08-08-2012 07:44 PM ET (US) From what I understand 2003 was the first year of the 60 4-stroke and it was 100% Fond du Lac manufactured, with larger displacement. [Gave his version of a short history of collaboration of Yamaha and Mercury on making engines.]
sosmerc	posted 08-08-2012 09:54 PM ET (US) The 2003 60hp Mercury engine that I was referring to stated on the serial tag: "Assembled in the USA with both foreign and us parts." The thermostat cover had the baked on black coating that totally resists any salt buildup, but the water passages behind the cover had no apparent coating and there was a lot of salt buildup. If ALL of the water passages had this black coating we would never experience any corrosion issues.
Stephen_12	posted 08-11-2012 09:38 AM ET (US) My 2005 Mercury is getting water in the oil. [This ambiguous mention of oil again prompted more inquires about which oil was being referred to.] [Finally Stephen tells us he means] the crankcase oil. I have torn down [the 2005 Mercury 90-HP FOURSTROKE outboard engine] now. I'm not seeing any problems with the head gasket. [The engine cooling water] may have been leaking from the water tube grommet into the oil sump. [Emphasis added--jimh.] I will re-assemble [the 2005 Mercury 90-HP engine] this weekend and will perform a pressure test of the cooling system to see if it has any other leaks. Seems like most people with this problem write it off to condensation but my engine was leaking saltwater into the oil. For those who have offerred to help, much thanks. When I get this sorted out, there will be more pictures.
Stephen_12	posted 08-11-2012 05:52 AM ET (US) [I have deleted several other threads that STEPHEN-12 started that discussed this problem and have apppended them to this thread. So now, finally, we have Stephen's discussion about his problems with his Mercury FOURSTROKE all in one thread and in the proper place. It has been about an hour's work to move all this around and get it into one place, but here we finally have the story, even if it is a bit disjointed and repetitious--jimh] I had been enjoying the smooth quiet power of my 2005 Mercury 90 HP four stroke when I happened to read all about the water in oil problems many were having. I changed my oil this Spring and about 1 cup of water and sludge came out. After flushing the engine with new oil, I read that these engines have to be run hard and that the thermostat has to be changed. Checking the thermostat revealed that it was stuck wide open so I replaces it and felt like I had done something good only to find that the engine oil was contaminated with water after only 2 trips on the boat. So I drained the oil and sampled the water that came out and found it to be salt water. Then I visited by local dealer who told me that the problem was pretty common and that it usually was due to a corroded adapter plate underneath the powerhead. So now I have the entire engine disassembled and don't see any problems with the adapter plate or gaskets in that area. I had checked compression and it was 110, 110, 105, 105. The engine runs very smooth and it will rev to 6000 RPM with an 18" prop on my Boston Whaler Montauk 170. Today I will disassemble the entire powerhead and look for cracks, corrosion, or a blown gasket. My friend at work has the same boat with a Honda 75 HP and we spoke and he found water in his oil. He pulled his engine apart and found a blown head gasket. He had low compression so it makes more sense than mine. Any suggestions?
Stephen_12	posted 08-11-2012 07:39 PM ET (US) I'll figure this out. But so far, no real clues as to where the water is coming from. The head gasket wasn't blown; the sump is like brand new; and the exhaust adapter plate and gasket looked pretty good. The head gasket comes apart in three pieces so it's hard to see what condition it was in before I removed it. There is no evidence of water entering any of the cyclinders and there is no rust or evidence of "steam cleaned" pistions. They all looked the same with a light carbon coating. The only thing I can find that's even slightly questionable is the water tube grommet where it connects to the adapter (exhaust) plate. If that thing leaks, the water will go into the oil sump. The grommet looked like it may have been weeping. [Emphasis added--jimh.] I cleaned up all the parts, checked the block and head for warping (they are within .001 inch each so that's not it, and await all the new seals and gaskets. I noted that Mercury superseded the part numbers for some of these items so there may be more to the story. Maybe the problem is that the seals and gaskets were no good from day one.
Jefecinco	posted 08-11-2012 07:48 PM ET (US) There have been cases of engines getting water in the crankcase when the engines have been mounted too low on the transom. I don't pretend to know how it happens but when a boat is abruptly slowed from on-plane speed it creates a large backwash which sometimes splashes water into the motorwell. If the engine is mounted low the backwash could come pretty high on the engine cowling. Some water could get under the cowling and find it's way into the crankcase. Pretty farfetched but perhaps worth your consideration. Butch
Stephen_12	posted 08-11-2012 07:53 PM ET (US) Here are some pictures of the engine: PIC1 PIC2 PIC3 PIC4 PIC5 [Note: there are many more pictures of the engine (without any captions) on the hosting side in that album.--jimh]
contender	posted 08-11-2012 09:04 PM ET (US) If you can not find a bad gasket then you have a crack somewhere, One day after the salt has set on one of your bearing the engine will stop--permanently
sosmerc	posted 08-14-2012 11:15 AM ET (US) Be sure to check the thermostat. If it's stuck open your engine will run too cold and this can cause a 4 stroke to "make oil". Actually it's adding condensation to the crankcase, and because the engine doesn't get up to proper temp the condensation fails to boil off. Also, the engine will run too rich because of improper temp.
jimh	posted 08-14-2012 08:13 PM ET (US) I finally found all the places where Stephen was posting about this problem and joined them to one thread.
Stephen_12	posted 08-18-2012 11:35 PM ET (US) For those that wanted to know how I determined that the water in my oil was salt water, I loosened the drain plug and out came about 4 ounces of clear water which I caught in a cup. Then the oil followed. I don't recommend doing this but I tasted [the water] quickly and it was very salty.
Stephen_12	posted 08-18-2012 11:40 PM ET (US) I am in the process of re-assembling the engine now. I made a jig up so that I could pressure test the block while it is off the mid section. I was able to pressure test the cooling system of the power head once I had the head back on with a new gasket. I brought it up to 20 psi with air and it held quite well so I am confident that I don't have a cracked block or head. I resealed the adapter plate (exhaust plate) and the oil sump and will try it out next week. Hopefully, it was the water tube o-ring area that was leaking into the sump.
jimh	posted 08-19-2012 10:20 AM ET (US) Stephen--I hope you had a shot of Scotch handy to get the taste of the contaminant out of your mouth. Thanks for the information. I once siphoned some gasoline and started it with suction by mouth; I think I can still taste that gasoline. Considering the volume of water you found and the tendency for this to be a constantly occurring problem, I agree with your analysis that the path for the water to enter the oil must have been some sort of leak in the cooling system. The prior discussions mentioning "making oil" in four-cycle outboard engines have all been focused on the oil becoming contaminated with condensation of water vapor or by blow-by of combustion chamber gases into the crankcase. These conditions are often associated with engines that operate at too low temperature due to poor regulation of the cooling. Your situation seems to be more likely to be a leak between the oil path and the cooling path. Also, kudos for tearing apart this complicated four-cycle outboard engine, and, we hope, putting it all back together. You now probably have greater knowledge of this engine than any reader.
Stephen_12	posted 08-20-2012 07:46 PM ET (US) For those who have been following this discussion, I completed the re-assembly yesterday and fired up the [2005 Mercury 90-HP FOURSTROKE using a hose adaptor]. It runs great--no difference, it always did--and after one hour of running, I let it sit and cool down and checked my oil. No water! I removed the drain plug and what came out was...OIL!. Then I ran [the 2005 Mercury 90-HP FOURSTROKE] for another hour using a plastic [water] tank and added cold water constantly to keep the tank cold enough. I sampled the oil, and, once again, no water. I have to question what Mercury Marine was trying to accomplish by putting the water tube and grommet through the oil sump. It would be a lot less risky if they routed it around the sump, as far away from the oil as possible. But their engineers must like to live on the edge so the water and oil are separated only by a grommet and about 1/4-inch of aluminum. [Emphasis added--jimh] I don't recall worrying about any of this with my previous Whaler and it's dependable 90 HP Mercury 3-cylinder 2-Cycle. Well, for now, the plan it to go back to boating and allow this pile of black nuts and bolts to sit on the back and behave itself while it pushes me around in pursuit of stiped bass.
fishforfun2	posted 03-20-2015 03:34 PM ET (US) [Revived this thread after several years of being dormant. Now expects participants from years ago to reply. Please note that it is not a good plan to expect people to be following a thread they started three years earlier--jimh] I have the same problem on my [2004 Mercury 115-HP FOURSTROKE]: water in oil every time I change it. Did changing the upper seal #12 part number 814080001 fix the problem or was it a different seal, Stephen? If that's the one, can I change it without removing the powerhead? Just remove lower end and mid section covers? Thanks--Dale
jimh	posted 03-21-2015 10:07 AM ET (US) As this thread was just revived, I have re-worked it to remove all the spurious comments and discussion, and tried to concentrate the information on the topic of contamination of the the lubricating oil of a 2005 Mercury 90-HP FOURSTROKE outboard engine with cooling water, in this case saltwater, that is apparently caused by a leak at a gasket or grommet or O-ring or seal of some sort where a cooling water pasagge in the enging block, in this discussion sometimes called "a tube", passes near to a portion of the block which is part of the oil circulation system, and cooling water can escape into the oil system.