Oil Leak
That is the shaft for the hand crank on this model engine. Not sure but would assume it has a regular old seal in there. You really need an engine manual to fix it right, but should be a pretty easy fix. I wouldn't pull the cover plate till you see a book on it. Some of these, there is lots of stuff connected together inside there. Basically I think you can just pull that cover plate off and replace the seal. I have a book around here someplace, and will try to check and let you know for sure whats in there.