Hey All,
Looking for some advise from owners of 2000 era F90-F115's that have dealt with water in cylinders.
Noticed milky oil at the start of the season. Cylinder #2 spark plug seemed cleaner than others and a compression test indicated it low (90psi) while all others were 150. Suspected head gasket but when I took it apart there was no obvious leak. Had the head surfaced, pressure tested, and valves ground, new seals. Re-assembled, seemed like it was running OK but noticed oil started to look watery. Engine started running rough and found water in cylinder #4. Compression was good across the board but I suspected I messed something up, I was using a suspect torque wrench and figured I wreaked the new head gasket? Removed, no obvious leaking, checked the block to confirm it was flat. No cracking visible anywhere on block. New head gasket, re-assembled and found it was running like shit right off the bad; not firing on #4, water on the spark plug. AHHHH!!!! When I took things apart cooling passages didn't seem too corroded...
From what I've read it sounds like the exhaust manifold is supposed to be dry and a water leak into the exhaust could cause water to get pulled into the cylinders. If this is the case seems like it would be most likely to happen to the bottom cylinder? I'm going to do a leakdown test to see if there is air leaking into the water jacket but assuming it tests OK can I get some input from people more familiar with the cooling systems on older F90-115's?I assumed that water would be purposely added to the exhaust at some point similar to an inboard but I don't know where that should happen (at what point should the exhaust be wet?). There is an exhaust cover on this motor; I had previously removed it, cleaned it, and re-installed with a new gasket. No obvious damage to either side of the assembly but does this cover separate water and dry exhaust and should it be double checked?.
Below the power head I see there is a gasket between the powerhead and exhaust guide. Do you think if the exhaust guide is corroded and/or the gasket has failed that water could get into cylinder #4? I'm reluctant to tear into things further at this point unless I am confident it could be a cause as the gaskets here are crazy expensive (already into it for $500+ in gaskets!!!). Luckily my times not worth anything![Wink](https://www.yamahaoutboardparts.com/core/images/smilies/wink.png)
If anyone has any suggestions on most probable places to check next please let me know!
Thanks,
Looking for some advise from owners of 2000 era F90-F115's that have dealt with water in cylinders.
Noticed milky oil at the start of the season. Cylinder #2 spark plug seemed cleaner than others and a compression test indicated it low (90psi) while all others were 150. Suspected head gasket but when I took it apart there was no obvious leak. Had the head surfaced, pressure tested, and valves ground, new seals. Re-assembled, seemed like it was running OK but noticed oil started to look watery. Engine started running rough and found water in cylinder #4. Compression was good across the board but I suspected I messed something up, I was using a suspect torque wrench and figured I wreaked the new head gasket? Removed, no obvious leaking, checked the block to confirm it was flat. No cracking visible anywhere on block. New head gasket, re-assembled and found it was running like shit right off the bad; not firing on #4, water on the spark plug. AHHHH!!!! When I took things apart cooling passages didn't seem too corroded...
From what I've read it sounds like the exhaust manifold is supposed to be dry and a water leak into the exhaust could cause water to get pulled into the cylinders. If this is the case seems like it would be most likely to happen to the bottom cylinder? I'm going to do a leakdown test to see if there is air leaking into the water jacket but assuming it tests OK can I get some input from people more familiar with the cooling systems on older F90-115's?I assumed that water would be purposely added to the exhaust at some point similar to an inboard but I don't know where that should happen (at what point should the exhaust be wet?). There is an exhaust cover on this motor; I had previously removed it, cleaned it, and re-installed with a new gasket. No obvious damage to either side of the assembly but does this cover separate water and dry exhaust and should it be double checked?.
Below the power head I see there is a gasket between the powerhead and exhaust guide. Do you think if the exhaust guide is corroded and/or the gasket has failed that water could get into cylinder #4? I'm reluctant to tear into things further at this point unless I am confident it could be a cause as the gaskets here are crazy expensive (already into it for $500+ in gaskets!!!). Luckily my times not worth anything
![Wink](https://www.yamahaoutboardparts.com/core/images/smilies/wink.png)
If anyone has any suggestions on most probable places to check next please let me know!
Thanks,
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