My son bought what appeared to be a good used 21" commercial Honda, HRC216. Got it home and noticed it was really low on oil so changed it, started it up, ran and mowed fine but leaks oil like crazy. Hard to be 100% certain but appears that it's coming from the top of the engine and I assume there's a top seal that may be bad but not sure there is and secondly, I have no idea how to change it if there is. I'm pretty mechanically inclined but hate to even tear into it without at least some basic knowledge. Anyone have any pointer, either in writing, diagrams of videos? So far can't find what I'm looking for so any help is greatly appreciated!