[Alex4188]

After a trip out last week I noticed some oil/exhaust looking mixture dripping down my prop, didn't look too alarming though. Took the boat out Saturday and washed her up when I got home and then this is what I found this morning. Blown lower seal? how do I fix this, any pointers or info would be a big help! thanks guys. the oil is not coming from that bolt, it is coming from behind the prop.

 

[Brett]

Wrong color to be a leaking lower unit.
What you see is leftover unburnt fuel/oil mixed with burnt fuel/oil (carbon).
Caused by an old tech 2 stroke running at low rpms ( like when rinsing the outboard)

 

[topnative2]

What he said!!!!

Check your plugs....

 

[cutrunner]

Its more than likely what Brett said, but... it very well could be a bad propshaft seal and that" could be" just some jet black gear oil. Yamahas arent known for being as in efficient with wasting fuel/oil mix as mercs and omc's

 

[Alex4188]

thanks guys, now that I think about it You hit the nail right on the head, I was trimmed up pretty high (1' of water) at idle speed most of the day. I made several location changes through out the day but only a few hundred yards at a time at idle speed and idled backs to the dock with the motor tilted up pretty high for about 2 miles. I'll do a lower unit gear oil change any way its probably due for one and change out the plug... thanks a lot guys!