Flight and Power Loss
During the climb to cruise altitude, the pilot noted a progressive loss of engine power. The pilot diverted the aircraft back toward the departure airport and attempted to restore power by activating the boost pump, moving the mixture to full rich, switching fuel tanks, and applying carburetor heat. Despite these efforts, the engine continued to lose power.
Emergency Landing
As the pilot maneuvered the aircraft onto a short final approach, the engine lost all power. The aircraft subsequently crash landed short of the runway in a swamp.
Post-Crash Examination
A post-crash examination of the engine revealed no evidence of mechanical failure. Several ounces of water and sediment were found in the carburetor bowl; however, during the crash and/or recovery of the aircraft, the fuel lines broke and the engine became nearly completely submerged in water. Several spark plugs were slightly fouled with black, sooty carbon deposits. The aircraft was equipped with a Supplemental Type Certificate (STC) to operate on auto-fuel and was serviced with 89 octane regular fuel. The carburetor was equipped with a composite float, which showed evidence of minor deterioration; however, during a flow check, the carburetor functioned properly.