On March 18, 2004, at 1430 eastern standard time, a Cessna 182K, N4GB, registered to and operated by the private pilot, collided with trees and subsequently the ground shortly after takeoff from the Cypress Lakes Subdivision, private grass strip, in Eden, Georgia. The flight was operated under the provision of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. The pilot received serious injuries and the airplane sustained substantial damage. The flight originated from the private air strip, Eden, Georgia, on March 18, 2004, at 1429. According to the pilot, he was conducting a test flight following the installation of an overhauled engine. Since the airplane had a supplemental type certificate for the use of automotive fuel, and it was recommended by the engine rebuild facility that the 100 low-lead aviation fuel be used in the rebuilt engine for the first 50 hours. Therefore, the mechanic drained the automotive fuel from the fuel system, and replaced it with 38 gallons of 100 low-lead aviation fuel. After ground runs of approximately 20-minutes with no problems noted he re-started the engine, did a standard run-up and taxied to the runway for a takeoff. According to a witness, shortly after takeoff, the engine lost power and the pilot attempted to return to the runway. As the pilot maneuvered for the forced landing, the airplane collided with the tops of trees, descended and collided with the runway, and flipped inverted. The pilot stated that he had been knocked unconscious in the accident and did not recall all of the events. However, he did remember that after takeoff the engine slowly went to idle on its own during the flight. The next thing he remembered was waking up in the hospital. The post-accident examination of the airplane found the engine and the empennage separated from the cabin and cockpit. Examination of the engine found the mixture control cable disconnected from the carburetor. The airplane was recovered to Atlanta Air Recovery where the engine was run. During the post-accident examination of the the airplane, the engine ran without any discrepancies after the mixture control cable was reconnected.