Incident Overview
A pilot experienced a partial loss of engine power momentarily before liftoff. Despite the power reduction, the takeoff was continued. Once airborne, the power loss reoccurred. The pilot dumped the load in an attempt to maintain flight, but the aircraft could not sustain sufficient altitude and impacted trees approximately 1 mile from the airport.
Post-Accident Inspection
Following the accident, an inspection of the engine revealed that the intake valves on cylinders #2 and #8 were tuliped and would not close. Additionally, the outlet tower blocks on the magneto for cylinders #2, #6, and #8 were crossfiring, which resulted in pre-ignition to those cylinders.