On August 25, 1996, at 1800 eastern daylight time, a Lake LA-250, N8405F, was substantially damaged during a forced landing near Hamilton Township, New Jersey. The certificated airline transport pilot and passenger were not injured. Visual meteorological conditions prevailed for the flight that originated at Montgomery, New York, about 1720. No flight plan had been filed for the flight conducted under 14 CFR Part 91. In the pilot's statement, he said that the airplane was at approximately 2,000 feet when a complete loss of engine power occurred. He further stated that he attempted to restart the engine without success. He then performed a forced landing to a farm road where the landing gear collapsed. About 30 gallons of fuel remained in the airplane's fuel tanks. Examination of the airplane by the NTSB Investigator revealed that there was no external damage to the engine. When the battery was activated, and the electric fuel pump was turned on, fuel leaked from the main fuel line connection at the fuel injection manifold. Examination of the fuel line revealed that the line nut was loose. When the nut was turned by finger pressure, it turned two flats (about 1/3 turn) before any resistance was noted. After the line nut was tightened, an engine start and run-up was successfully completed. A review of the airplane's maintenance records revealed that during the last annual inspection, in March 1996, two engine cylinders were replaced. Also, the fuel injectors were cleaned, and a fuel injector line Airworthiness Directive was complied with. The airplane had been flown about 37 hours since the annual inspection.