The pilot stated that he hand-propped the engine, boarded the airplane, and began to taxi and that, shortly thereafter, the engine "sputtered and stalled." He then realized that he had left the fuel selector in the "off" position. He set the parking brake, turned the fuel on, exited the airplane, and hand-propped the engine again. The engine started and ran at a high rpm. The airplane moved forward and began to spin in circles. The pilot attempted to get back in the cockpit; however, the door had swung closed, and the airplane struck him, knocking him to the ground. The airplane spun a few more times before striking a hangar, which resulted in substantial damage to the right wing, and coming to a stop. Afterward, the pilot recalled that he had forgotten to retard the throttle before attempting the second engine start. The airplane was not equipped with an electric starter.