On November 21, 2004, about 1630 eastern standard time, a Cessna 172B, N7493X, registered to and operated by a private individual as a Title 14 CFR Part 91 personal flight, impacted parked airplanes in Zephyrhills, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The private-rated pilot received serious injuries, and the airplane incurred substantial damage. The pilot stated that he had flown his airplane from Lakeland, Florida, to Zephyrhills, Florida, for fuel. After refueling he got in and tried to start the airplane, and said that it would not start. He said he turned off the magneto switch, set the brakes, got out the airplane, and tried starting it by hand several times, but it would not start. About that time a person drove up and asked him for directions, and after providing the person with information he said that when he next pulled the propeller, the engine started operating immediately, and its speed increased. The airplane started moving forward and the pilot said he jumped out of the way. He said it veered to the left and was heading toward the fuel tank, so the pilot said he ran after it and grabbed the left strut to keep it from hitting the tank. The airplane proceeded between the fuel tank and the credit card machine, and in the process the pilot said he was knocked to the ground. As the airplane continued on, the pilot said it impacted two parked airplanes, as well as two chain linked fences. The airplane's entanglement in the second fence caused the engine to cease operating, and as a result, the airplane stopped moving.