On the day of the accident, the pilot had to get the airplane jumpstarted as the battery was low on energy. Later during his flight home, he landed at an airport to refuel. After refueling, he attempted to start the engine. The battery however, was too weak to start the engine. The pilot then checked the parking brake was engaged and got out to look for his portable jump starter pack in the storage compartment. It was not however onboard. He then proceeded to look for someone to assist in starting. Not finding anyone, he went back to the airplane and set the mixture to full rich, opened the throttle about 10 percent, primed the engine about 8 to 10 times, turned the magneto switch to "BOTH", checked the parking brake, and attempted to hand-prop the engine twice without success. He then checked these items again and once again attempted to hand-prop the engine. The engine still failed to start. He assumed the engine was flooded. Therefore, he set the mixture to idle cutoff, turned off the magnetos, and checked the parking brake once again. He then got out of the aircraft and prior to touching the propeller, visually looked in the cabin to check that the key for the magneto switch wasn't in the "BOTH" position. He then hand-propped it. A puff of smoke came out of the exhaust, and the engine suddenly accelerated to maximum rpm. He immediately moved from in front of the propeller. He then thought "the brakes are on, don't worry", then noticed that the airplane was moving and picking up speed. At this point, he was in front of the right wing. He then attempted to grab hold of the door, hop on wing and get into the airplane. He could not however get a grip on door as the slipstream from the propeller pushed it shut. He was then dragged and run over by the airplane. The airplane then made contact with a ditch and was substantially damaged. The pilot advised that he had been having problems with the battery holding a charge, and that he should have replaced it. He also advised that apparently one magneto was still on; he should have used chocks, and should not have attempted to hand-prop it by himself.