# Oil seal leak?



## Smackdaddy53 (Dec 31, 2012)

If it looks milky when you drain it you likely have water intrusion through the shaft seal. If it’s blacker than normal you just need to change it IMO.


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## yobata (Jul 14, 2015)

Smackdaddy53 said:


> If it looks milky when you drain it you likely have water intrusion through the shaft seal. If it’s blacker than normal you just need to change it IMO.


It's way blacker than normal, I just changed it like 4 months ago... that's why I'm hesitating a bit, maybe it's not lower unit oil??


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## Guest (Jun 27, 2018)

Pull the prop and check for fishing line.
I am leaning towards unspent 2stroke. They will do that from time to time. Check you LU oil and replace. Get a bottle of Yamaha ring free and a new set of plugs and do a shock treat “directions on bottle” Change plugs after treatment. I reccomend doing the preventative dose after that each tank full. That ratio is something like 1oz to 10 gallons so don’t get sticker shock when ya see the cost of the ring free. I can tell you this one is not snake oil and works very good!


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## yobata (Jul 14, 2015)

Well I didn't find any fishing line on the shaft in front of the prop. I also couldn't pull off the barring carrier that allows access to pull off this shaft seals, so I just ended up changing the lower unit oil. Here is what it looked like: 









I wouldn't say that's "milky".

I'm going to chalk this up to outboard 2 stroke oil exhaust for now but will be monitoring it. Thoughts?


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## Pole Position (Apr 3, 2016)

Couldn't resist.....


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## Smackdaddy53 (Dec 31, 2012)

If the LU oil is not milky and it’s just darkee than normal I’d lean towards no issues. Unburned 2 stroke residue is normal. All my river boat 2 strokes do it. Run it in a big container of water for about 10-15 minutes and you will notice a ring of oil forming on top of the water.


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## Guest (Jun 27, 2018)

Try the ring free, carbon builds up in the exhaust and holds onto that unspent oil until saturated. Once that happens it starts dripping like that regularly. I swear by the stuff!


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## Smackdaddy53 (Dec 31, 2012)

Boatbrains said:


> Try the ring free, carbon builds up in the exhaust and holds onto that unspent oil until saturated. Once that happens it starts dripping like that regularly. I swear by the stuff!


The previous owner of my Yamaha 70 used RingFree since the motor was new in 2001, I continued and the motor still runs like a top and strong. No dripping oil though.


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## No Bait / Lures Only (Apr 10, 2011)

Only other item it may be is a bent prop shaft, as my 25 would and wouldn't leak depending on prop orientation.


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## JMZ400 (Aug 30, 2015)

May seem silly, but you're sure it's not coming down lower unit from up above. I overfilled my oil tank and when not level it was leaking down side of motor. Not even sure if your is oil injection...


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## SomaliPirate (Feb 5, 2016)

I third the motion for ring free.


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## yobata (Jul 14, 2015)

JMZ400 said:


> May seem silly, but you're sure it's not coming down lower unit from up above. I overfilled my oil tank and when not level it was leaking down side of motor. Not even sure if your is oil injection...


The 2006 2 stroke 25ESH version is a mix in the gas tank style...

I have not seen the leak since I changed the LU oil. I highly suspect now that it was in fact exhaust oil


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## RunningOnEmpty (Jun 20, 2015)

Others mentioned ring free and I agree. I have my Yamaha torn apart right now and everything looks nice. Too bad the head rotted out just in time for my vacation


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