On October 28, 2004, at 0930 Pacific daylight time, a Champion 7GCAA (Citabria), N9081L, collided with a tied down Cessna 182 on the ground after the engine started at Petaluma Airport, Petaluma, California. The pilot operated the airplane under the provisions of 14 CFR Part 91. The private pilot and passenger were not injured, and the airplane was substantially damaged. Visual meteorological conditions prevailed, and a flight plan had not been filed for the local area personal flight. The pilot stated to the National Transportation Safety Board investigator that he was attempting to start the plane with the electric starter but after each attempt the battery got weaker. He saw a white puff of smoke come out the left front side of the engine cowl. He exited the airplane and examined the engine; he then adjusted the propeller with his hand and the airplane started. Surprised by the sudden start, the pilot jumped to the side and attempted to arrest the airplane's movement by grabbing on to the right wing strut. His attempt failed and the airplane taxied into another parked airplane, striking it directly in its right front side. The pilot said that he had left the magneto switch in the "on" position. The passenger in the rear seat of the plane was not a pilot, and did not know how to apply the airplane's brakes. The pilot said that he was not trying to hand-prop the engine. A witness stated that he saw the airplane racing across the ramp at full throttle with the left engine cowl open. The pilot's operating manual for the Champion 7GCAA states in the before starting checklist to set the brakes, and in the starting checklist to crack the throttle open 1/2 to 1 inch. In the shutdown checklist the brakes are to be set, electrical equipment off, mixture - idle cut off, and magnetos off.