DURING THE TAKEOFF CLIMB THE PILOT SMELLED WHAT HE THOUGHT WAS BURNING ELECTRICAL WIRES, AND THE COCKPIT FILLED WITH SMOKE. THE ENGINE LOST ALL POWER ALMOST IMMEDIATELY. THE OFF AIRPORT FORCED LANDING ON THE MUD FLATS RESULTED IN SUBSTANTIAL DAMAGE TO THE AIRPLANE WHEN IT NOSED OVER. EXAMINATION FOUND THAT THE VOLTAGE REGULATOR HAD SHORTED OUT. THIS CAUSED A BRIEF LOCALIZED FIRE WHICH BURNED AND SHORTED OUT THE MAGNETO 'P' LEADS, CAUSING THE ENGINE TO STOP RUNNING.