On July 12, 2000, about 1230 eastern daylight time, a Aeronca 65-TC, N29419, registered to a private owner, collided with a wire then the ground while descending for a forced landing shortly after takeoff from the Boomerang Airport, Harris, North Carolina. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 personal flight. The airplane was substantially damaged and the private-rated pilot, the sole occupant, was not injured. The flight originated about 1 minute earlier. The airplane was fueled with automotive fuel before takeoff from the Big Oaks Airport, and flew and landed at the Boomerang Airport. After landing, the pilot left the engine running then elected to depart. During the initial climb about 50-100 feet above ground level, the engine experienced a loss of power; insufficient power remained to sustain flight. He initiated a shallow right bank and after realizing he was unable to return to the airport, he turned towards a nearby river for a forced landing on a sandbar. While descending to fly beneath a trestle bridge that was between his location and the sandbar, the airplane collided with a wire beneath the bridge. The airplane veered to the right, descended and impacted with "scrub trees/saplings" on a side of the river. The airplane was recovered. Postaccident, the airplane was inspected by a Federal Aviation Administration (FAA) certificated mechanic with inspection authorization (IA). Fuel flow testing was performed which revealed that with fuel supplied to the fuel tank and the flexible fuel line removed from the carburetor inlet, it took approximately 14 minutes to fill a gallon container. Continued testing revealed "rust" exited a hard aluminum fuel line between the outlet of the "header" tank to the inlet of the fuel shut-off valve. The lines were cleared and flow testing revealed it took approximately 2 minutes 4 seconds to fill a gallon container. Additionally, cold differential compression testing of each cylinder revealed no cylinder was greater than 52 psi when using 80 psi as a reference. A copy of the statement from the IA is an attachment to this report. The airplane was inspected last in accordance with an annual inspection on February 3, 2000; the pilot indicated that the airplane had accumulated approximately 20 hours since then at the time of the accident. No inspections were recorded between a periodic inspection on June 8, 1963, and an annual inspection December 12, 1994. The December 1994 entry indicates, "Assembled aircraft after long term storage...." There was no record of any fuel lines being replaced. Copies of maintenance records are an attachment to this report.