19980629015249A

Lost power. Crashed. Plastic lodged in fuel line. (.4)the experimental airplane was on climbout following a touch-and-go landing. During the climb, the engine began sputtering and lost power. The airplane leveled off momentarily and then began a steep left turn back toward the runway. During the turn, the airplane descended and collided with a power line. The engine had lost power in flight on several prior occasions. The airplane was not equipped with a fuel boost pump or an engine-driven fuel pump. The fuel tank was mounted in the fuselage, immediately forward of the instrument panel with no accumulator tank. The headspace between the fuel tank and the carburetor was reduced whenever the airplane's pitch attitude increased. A minimum of 0.5 pounds of fuel pressure at the carburetor inlet is required for operation of the engine. The minimum flow volume required for engine operation is not specified. The tank had a single, under wing vent line. Dirt and a piece of plastic were found lodged in the 90-degree elbow of the fuel tank vent line at the point where the line enters the tank. The dirt had formed a ball and was located on the tank side of the piece of plastic. The fuel tank was also equipped with a vented fuel cap that was found in place; however, the vent hole in the cap had been covered with gray silicon sealant. (-23) no narrative.