THE PILOT'S FAILURE TO MAINTAIN AIRCRAFT CONTROL WHICH RESULTED IN AN INADVERTENT STALL, AND HIS IMPROPER EXECUTION OF EMERGENCY PROCEDURES. FACTORS WERE THE PILOT'S OVERCONFIDENCE, HIS INADEQUATE PREFLIGHT INSPECTION WHEN HE FAILED TO DRAIN THE GASCOLATOR, THE WATER CONTAMINATION IN THE FUEL, AND THE LEAKING FUEL TANK CAP.