What happened
The flight was conducted as part of a 'clown act' during an air show. Shortly after takeoff, the engine lost power while the pilot was performing pitching maneuvers. The pilot attempted to regain power by pumping the throttle but was unsuccessful. The airplane subsequently impacted trees.
The investigation
A post-crash examination of the airplane revealed that the gascolator was about 90% full of water and 10% full of fuel. However, the contents of the carburetor were mostly fuel with about 1 to 2 teaspoons of water. A small amount of trash was also present in fuel that was drained from the carburetor. The carburetor was not equipped with an accelerator pump. No water was found in the fuel tank. The pilot reported that no water was obtained when fuel was drained from the fuel tank prior to flight.
Findings
The primary issue was water contamination in the fuel system, specifically accumulating in the gascolator. The lack of an accelerator pump on the carburetor likely contributed to the inability to clear the water or maintain power during the maneuvering.