Incident
After departure, at an altitude of approximately 500 feet above ground level, the 2,100-hour pilot reported that the engine "lost most of its power output." The pilot applied carburetor heat and did not notice improvement. To avoid an approaching tree line, the pilot banked the airplane slightly to the right and initiated an emergency landing to an open grass field. Subsequently, the airplane impacted terrain.
Pilot Report and Fuel Information
The pilot stated that the airplane was last refueled using fuel from five five-gallon plastic containers prior to the flight. He noted that there were 12 gallons of fuel in the left fuel tank and three gallons in the right fuel tank.
Fuel System Examination
Examination of the airplane's fuel system revealed a light brown milky substance in the carburetor bowl and both wing fuel tanks. Water was observed in one of the five containers used for refueling.
Engine Test
The engine was successfully run for 30 minutes at various power settings on a test bench and was noted to be free of anomalies.