The pilot stated that following preflight inspection of the airplane he attempted to start the engine using the starter but was unable. He indicated this to be, "an on-and-off issue…" in that he had to hand start the engine once during 5 attempts prior to 5 separate flights the previous weekend. He elected to hand start the engine without assistance because he was unable to locate personnel from the fixed base operator, and asked the non-rated passenger seated in the right front seat to apply the aircraft's brakes. With the airplane unsecured and the throttle applied "a little bit", the engine started. Initially the airplane did not move, but then began to move. He attempted to board the airplane but was unable and it began travelling faster. The airplane turned to the left, went between 2 rows of airplanes and impacted several parked unoccupied airplanes. The pilot further stated that he did not show the passenger how to activate the aircraft's brakes, and believes the passenger may have inadvertently applied left rudder in an attempt to stop the airplane, although the passenger told him he did not recall doing so. There were no injuries to the front or rear seat passengers, and there were no ground injuries. The Federal Aviation Administration (FAA) Pilot's Handbook of Aeronautical Knowledge contains a section titled, "Hand Propping" which indicates to never allow a person unfamiliar with the controls to occupy the pilot's seat when hand propping. The section also indicates that an additional precaution includes placement of chalks in front of the main tires or if not feasible, the airplane's tail may be securely tied. The excerpts are contained in the NTSB public docket.