The pilot stated that during preflight inspection of his Cessna 205, on the day prior to the accident, he had noticed that the seals on the fuel caps were worn. He replaced them with fuel caps borrowed from a friend’s airplane, a Cessna 182. Following the preflight, he departed for a local airport for fuel and then returned. Upon his return he had noticed "gas streaking on top of the wings," but assumed that the fuel vents had discharged some fuel. On the day of the accident he checked the weather and departed with a passenger for a cross-country flight. While en route, the engine "coughed;" he turned on the fuel boost pump and switched the fuel selector from the right to the left tank, after which the engine restarted. The pilot noted that the fuel gauges were fluctuating in-flight between empty and one-quarter tank. Believing that he had sufficient fuel on board, he made a descent and continued towards his destination. Minutes later the engine quit, the pilot switched the fuel selector from the left tank to the right tank, and made a turn for a local airport. Realizing that he would not make it to the airport, the pilot elected to land in a field. The airplane touched down on rough terrain and the nose strut sheared off. The airplane then dug into the ground and flipped over. The propeller, landing gear, wings, fuselage, and empennage incurred damage. The pilot stated that he had replaced the seals in the borrowed caps in order to prevent water from leaking into the fuel, but that the new seals did not fit as tightly and that fuel must have been "sucked" out of the tanks.