Water in lower unit?

[Douglasdzaster]

Hello everyone. I’m finally going to take the boat I’ve been working on so long on a night fishing trip with my so this week.
Since it hasn’t been started in quite awhile. I went through the outboard today (1982 40hp 2 stroke Yamaha) trying to do any preventative maintenance I can. We’re on major water restrictions here and I can’t run the outboard here at the house. I’m loading up tools in a couple of days and going to a small lake to test run everything.
I change the lower unit oil which didn’t have very many hours on it but was a li over a year old. When I pulled the plug I saw what I think was water coming out. It wasn’t milky but Carmel color and not very much. When I removed the top plug more came out. It was all in the bottom of the unit though. I thought water went to the top of oil. After the pan sit for around 5 minutes it was completely gone. I tilted the pan and it had made a layer in the bottom of the pan. I changed the washers on both plugs after refilling it.
After I put a little time on it I’ll remove the bottom plug and see if it’s in the new oil.
Anyone have an experience with their lower unit they could share? I want to catch whatever is going on before it turns into a major fix.

 

[Still Afloat]

Oil and gas are lighter than water. The prop shaft seal is probably leaking. Maybe it picked up some fishing line at some point and that damaged the seal. Replace the seal and check the bearings for excessive play while you are at it.

That can be real bad news up here in Moose country if you don’t catch it before freezing temperatures.

 

[MrGiggles]

Water is heavier than oil, depending on the brand of gear oil and how long it's been sitting, it will either separate and sit at the bottom, or emulsify.

There should not be water in it, time to pressure test and see where the leak is.

 

[Douglasdzaster]

Water is heavier than oil, depending on the brand of gear oil and how long it's been sitting, it will either separate and sit at the bottom, or emulsify.

There should not be water in it, time to pressure test and see where the leak is.

Thank y’all for the help. I was in more of a panic than a thinking mode. I knew water went to the bottom of gas for sure as many samples I’ve taken over the years in glass jars.
Im now educated on the power head after two years. Now it’s time to research how to pressure test the gear case and replace the seals.
One of the seals I replaced on the plugs yesterday looked deformed. One can only hope this is the problem.
I use the Mercury high performance gear oil the clams to help with water intrusion when it happens and doesn’t foam.
Thank again I appreciate it: Douglas

 

[Pappy]

First off don't jump to conclusions that the propshaft seal failed. Do check it by removing the prop and do a visual check.
Second - Are your fill and drain plugs sporting a reddish colored sealing washer? If so those were changed several years back to a newer black one that needs to be changed with every gear oil service. The older reddish ones were found to be more prone to crushing and allowing the screw torque to back off and creating a bit of water seepage into the gearcase. Get some new fill and drain screw seals first and try that.

 

[Douglasdzaster]

First off don't jump to conclusions that the propshaft seal failed. Do check it by removing the prop and do a visual check.
Second - Are your fill and drain plugs sporting a reddish colored sealing washer? If so those were changed several years back to a newer black one that needs to be changed with every gear oil service. The older reddish ones were found to be more prone to crushing and allowing the screw torque to back off and creating a bit of water seepage into the gearcase. Get some new fill and drain screw seals first and try that.

Thanks Pappy. I have the black seals but didn’t replace them last time I changed the fluid. I have a small stash of Yamaha parts for the outboard and had the OEM seals on hand yesterday and installed them this time. After a little dip to get the motor right from sitting so long I’ll pull the bottom plug and see what comes out since the water would be right there. Is no water I’ll top it back off and replace the seals again.
I need to add I did remove the prop and where the shaft goes in was some old crusty grease which I removed. I didn’t find any type of fishing line or other debris. The seal looked ok to me. No cracks or distortion. I’d course that was the first time I’d ever inspected one.
If I do get more water I’m going to investigate what it takes to pressure it up with air and check for leaks.

 

[thill]

Agree with Pappy. That sounds like a pretty minor leak. Monitor it. Sometimes it happens again, sometimes not.

I had a motor that had a little water in the gearcase. Maybe a tablespoon. I drained it, added fresh, and for a year or two I checked it again and again, but never found even a trace of water. My guess is that was the original oil from the factory, and some water got in somewhere in its lifetime, but it wasn't an issue currently.

Hopefully, this is how yours will be.