On April 21, 2007, about 1918 eastern daylight time, a Carter A. Smith, Wheeler Exp 2000, amateur built airplane, had a loss of engine power and was ditched in the St. Lucie River at Stuart, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the flight from Lakeland, Florida, to Witham Field (SUA), Stuart, Florida. The airline transport-rated pilot received minor injuries and the airplane received substantial damage. The flight originated from Lakeland, the same day, about 1830, and was conducted under the provisions of 14 Code of Federal Regulations. The pilot stated he was on a left base leg for runway 7 at SUA when the engine failed for an unknown reason. He set up for an off airport landing in a nearby river. After impact he exited the airplane through the left door. The airplane was recovered from the river and the engine was removed and taken to an engine overhaul facility for disassembly. Personnel from the overhaul company reported they completely disassembled the engine. No defects were found with the reciprocating mass or any other major engine components. The engine had sustained corrosion damage due to salt water contamination. The engine-driven fuel pump was sent to an accessory overhaul company for examination. The engine-driven fuel pump drive shaft was found sheared and contamination was found inside the pump. The contamination was reported to be a rubber type substance. During removal of the engine from the airplane the fuel line fitting on the inlet side of the engine-driven fuel pump was found separated. According to an FAA inspector it appeared the fuel line fitting had been rubbing on the battery box. The separated fitting was sent to the National Transportation Safety Board Materials Laboratory, Washington, D.C. Examination showed the fracture on the fitting was a result of overstress separation, There was no indication of any pre-existing damage or fatigue. The airplane was equipped with an electronic flight information system that had data storage capability. The system was removed from the airplane and shipped to an overhaul facility for readout. Representatives from the facility stated that the system had been damaged by water submersion and they were unable to recover any data from the unit.