On Sunday, September 5, 1993, at 1635 eastern daylight time, an amphibian Cessna 206, N2147F, owned, operated, and piloted by Edward Stafford of Old Forge, New York, lost total engine power during climb-out from Seventh Lake in Inlet, New York. The pilot maneuvered the airplane to a nearby lake and made an emergency landing. The pilot and two passengers were not injured. The airplane was substantially damaged. Visual meteorological conditions prevailed at the time of the accident. The flight was conducted under 14 CFR Part 91. The pilot reported that shortly after takeoff, at about 300 to 400 feet above terrain covered with "high" trees, the airplane's engine lost total power. The pilot stated that after the engine lost power, "A sharp right turn followed by a sharp left turn was made to line up with 6th Lake. Aircraft landed in Sixth Lake in the water about 200 ft from shore. The aircraft sustained substantial damage but did not sink...." Post accident examination of the engine and fuel system was accomplished by Mr. J. Payne, owner of Payne's Air Service located in Inlet, New York. Mr. Payne stated, "I found a flat piece of material in the fuel header tank which looked like material from the interior of a wing fuel bladder tank. The piece was about 3/8 of an inch wide and 3/4 of an inch long." Mr. Payne stated that he was able to manipulate the material inside the header tank to cover the fuel port which leads to the fuel pump. He said when the material covered the fuel port, fuel flow to the fuel pump was blocked. Mr. Payne noted that the airplane's wing bladder fuel tanks and their fuel screens were intact. He stated that the piece of material found in the fuel header tank was too big to have been able to pass through the wing bladder fuel tank screens. The origin of the material found in the fuel header tank was not determined. During the post accident examination of the airplane, it was noted that the airplane's original wing bladder fuel tanks were no longer installed. Mr. Payne stated that he remembered the airplane's fuel bladder tanks being removed and replaced sometime prior to this accident.