Why do wires get hot on a 16 hp Kohler?

I have an Kohler Pro 16 ohp ohv engine on a 42" Craftsman riding mower that I purchased new 5/8/99. Two wires coming from the regulator/rectifier (credit card shaped piece with three wire connectors screwed onto the outside of the flywheel housing) became so hot that they burnt in two and blew the 15 amp fuse. I replaced the fuse, twisted the wires back together and it started right up. After about two minutes, however, I felt the wires and they were VERY warm. What would cause this and how can I fix it? What does the Stator assembly do? Any help would be greatly appreciated. If it helps: engine family: SKH426U1G2RB, model #: CV16S, Spec. #: 43519, 426 cc.