I have a 1989 Yamaha 130HP that is leaking black oil down the outer shaft. It is coming from where the cowl meets the lower unit and leaking out the bottom of the apron down the shaft.
Impalor19, welcome to iBoats.
We need to see some pictuees of your issue. The link you provided looks like excess oil residue in the exhaust leaking out of the lower cowl.
After 3 posts, you will be able to post pictures. The best method is option 3 of this link : http://forums.iboats.com/forum/forum-rules-and-guidelines/9938375-photo-upload-tutorial
clean it up well and look where it is coming from.
probably gasket leaking as exhaust related unburned carbon fouled oil should not be coming from up there usually comes out the exhaust
i have a limited experience with Johnson and that is more to 9.9 but i would suspect the lower main crank seal. i am on a 9.9 lake and have seen that several times
lower crank seal would be letting oil out down the drive shaft and it would not be black carbon fowled, should be unburned clean 2 stroke oil out of crankcase