Incident Overview
After a pre-departure engine run-up with no discrepancies, the pilot took off from an 8,501-foot runway. Shortly after takeoff, the engine experienced a partial loss of power. The pilot verified the positions of the propeller, fuel selector, and mixture controls, and checked the rpm and manifold pressure gauges. The engine power was restored sufficiently to maintain level flight, but with insufficient runway remaining, the pilot elected to maneuver for a return landing. During the approach, the engine again experienced a partial loss of power. While descending for a forced landing on a road, the airplane collided with the top of a chain link fence, then struck the ground and a road sign pole before coming to rest upright.
Post-Incident Examination
An FAA airworthiness inspector examined the airplane and found two ignition leads inoperative and two cylinders with low compression. Additionally, gasket material was found lodged between the carburetor throat and the upper portion of the venturi. The gasket material was the exact shape of a piece missing between the carburetor mount flange and the airbox assembly.