Accident Overview
During the initial climb after takeoff, the engine lost power. The aircraft subsequently collided with trees and crashed.
Fuel System Examination
Water was found in a fuel line located between the fuel selector valve and the electric fuel pump, in the electric boost pump manifold, and in the carburetor inlet strainer. However, the fuel system was damaged during impact and fire suppressant chemicals had been sprayed on the wreckage.
Carburetor Inspection
A check of the carburetor showed that it was providing a lean mixture at low power settings and a rich mixture at high power settings. A teardown of the carburetor revealed a crystalline substance on the carburetor diaphragm, an improper metering jet, and that five shims were installed in the carburetor regulator diaphragm spring mechanism. The Bendix overhaul manual allowed a maximum of two shims.
Post-Accident Engine Check
During a post-accident check, the engine operated normally with the electric fuel pump on, but the engine stopped running when the electric pump was turned off.