Black residue from drain hole in cowling

[mooser_24]

I have a 25 hp 2 stroke with about 30 hours. Recently I have found that after *****ing for some time and then running the motor wide open a black residue come out of what looks to be a drain hole on the bottom of the cowling. This hole right beside a bolt that goes up through the cowling and into the engine block on the tiller side of the motor. The residue runs down the shaft and makes a mess. Is there a problem here and what are the fixes?

[boats.net]

It is unburned gas going through exhaust passages and washing down carbon from exhaust. I'm not sure where you are talking about the hole, but look for a bad gasket at base of engine.