The aircraft nosed over during a forced landing after a power loss. Several weeks prior to this accident, the aircraft made a precautionary landing due to a rough running engine. The aircraft was examined and 1 gallon of water was found in the fuel lines. The water was drained and the fuel filters changed, and the aircraft was flown back to York. On the day of the accident, the pilot checked with the FBO manager to confirm that there were no problems and did a complete pre-flight with attention to the fuel system. Very little water was found in the tank drains or engine sump. The aircraft was taxied for 20 minutes and a run-up performed with no engine roughness. Takeoff was initiated and at 450 feet AGL the engine stopped. According to the pilot, the engine regained power for about 10 seconds. When a turn was made, the engine quit again. A forced landing was made in a plowed field and the aircraft nosed over.