the red piug has the diode on the stator side. 3amp dc unregulated for charging battery. one red lead from stator ,dioade encased in connector, lets voltage flow one way, and is shorted.
There has to be a diode to convert the A/C to D/C current , the stater is a alternator that generates A/C current the diode should allow current to go in one direction only which would make it D/C. Slide your fingers down the black wire and feel for a fat spot or look for some heat shrink. The diode can go bad and no current go either way or can go bad and go both ways like in your case. Hope this link helps, http://www.darren-criss.org/single-wire-alternator-wiring-diagram/briggs-and-stratton-alternator-wiring-diagram-e6e93ddfe460daa9.html
Your stator winding may be fried,too. ebay has alot the stators ,and buy one wire red plug.can be upgraded to one with regulator three wire,stator two black wires and yellow plug.10 amp. or stator with green plug one wire, reg two wire. 5amp.so you're saying that the little plug that the Stator plugs into is a small diode in that plug and, if so i could probably pickup a 3amp from radio shack or something like that and wire it in the red wire
Your stator winding may be fried,too. ebay has alot the stators ,and buy one wire red plug.can be upgraded to one with regulator three wire,stator two black wires and yellow plug.10 amp. or stator with green plug one wire, reg two wire. 5amp.