Background
The airplane was parked outside on a ramp for several months. During this period, the fuel drains were removed and the fuel tanks were drained. An A&P mechanic later replaced the fuel drain in the right tank and added fuel for a maintenance ferry flight.
First Flight
The pilot performed a preflight inspection and before-takeoff checks. During taxi, the engine stalled once. After takeoff, the engine began to miss and run roughly. The pilot returned and drained the fuel sumps, finding a small amount of water in the gascolator. He then drained an additional gallon of fuel from the tank but did not find any additional water or sediment.
Second Flight and Ditching
After the first flight, the mechanic did not perform or offer any additional troubleshooting procedures. The pilot then took off again. After takeoff, the engine began surging and then quit. Attempts to restart the engine were unsuccessful. The pilot turned back toward the airport but could not reach the runway and ditched the airplane in the water.
Post-Accident Examination
The inside of the gascolator was coated with an insoluble greenish-brown film. The left wing fuel quantity transmitter was coated with material similar in appearance to a non-silicon sealant. This material was decomposing and readily flaked off when touched. About 10 cubic centimeters of liquid was recovered from the fuel reservoir; approximately half of this liquid was water, with a heavier sediment that was similar in color and consistency to the material coating the fuel quantity transmitter. The noted discrepancies were located in areas that would not be accessible or serviceable by a pilot performing a preflight inspection.