What happened
During cruise flight, the pilot observed a decrease in engine RPM. In an attempt to restore power, the pilot switched fuel tanks and applied carburetor heat. The pilot reported that the only effective measure was moving the throttle in an "in and out motion."
When the engine failed to regain power, the pilot attempted a forced landing in a pasture. The aircraft subsequently impacted the ground.
The investigation
The engine was removed from the aircraft and placed on a test stand for evaluation. The test was conducted using all original components present at the time of the accident, with the exception of the carburetor. The engine test run did not reveal any mechanical discrepancies.
Upon inspection, the carburetor was found to have sustained impact damage, specifically that the throttle valve had separated from the carburetor body. Further disassembly of the carburetor revealed that the gasket was dry and in pieces, and no fuel was present in the bowl.