I read up on you and this guys deal with this motor.

From what it looks like you paid $40 for a running motor. Seems like it has a bad head gasket. It still runs right? Just poorly since a part needs to be replaced. For a $40 motor what did you expect? Thats a good deal even if you have to replace parts.

Usually when swapping a motor wouldn't you want to change out wear and tear parts including gaskets, belts, pumps?

Dude does sound shady though looking at his I-trader.