What happened
Following departure from a private airport, the pilot attempted to level off the aircraft when the engine began running rough. In an effort to stabilize the engine, the pilot increased the mixture, which resulted in an increase in engine RPM and a period of smooth operation. However, the engine subsequently returned to a rough-running state.
The pilot then initiated a right descending turn, during which the engine ceased operation entirely. This loss of power necessitated a forced landing into a wooded area. The pilot was not injured in the accident.
The investigation
During the post-accident investigation, the pilot indicated a high level of certainty that the left fuel tank had been selected for use. Upon physical examination of the aircraft's fuel system, investigators discovered that the aft fuel supply line located in the left wing was obstructed with insect larva.
To further evaluate the engine's condition, the engine assembly was removed from the aircraft and placed on a test stand. During this testing, the engine started, operated correctly, and developed sufficient power.