What happened
The pilot was attempting to hand-prop the aircraft without assistance. To secure the plane, the pilot placed chocks both in front of and behind the right main gear. After several unsuccessful attempts, the engine successfully started. The pilot described the engine running at a power level sounding like full power, even though the throttle was set to idle.
As the pilot attempted to enter the cockpit, the aircraft jumped over the chocks and began to move across the ramp. In an effort to prevent the aircraft from striking a parked Seneca, the pilot grabbed the wing strut to steer the plane. The pilot released the strut when it appeared the aircraft was heading toward the runway rather than the ramp area.
During the excursion, the left wing of the aircraft struck fuel pumps, causing the plane to swing around and strike the pilot. The aircraft continued moving toward the ramp, where it collided with a parked Cessna 172 and a chain-link fence before finally coming to a stop. The pilot was injured during the collision.
Findings
At the time of the engine start, the magnetos and fuel selector were in the on position, but the throttle remained at the idle position.