The airplane was substantially damaged at about 0940 Eastern time during a forced landing following an in-flight loss of engine power. The solo airline transport pilot was not injured. Day, visual conditions prevailed. About 20 minutes into the flight, the engine began to lose power. The pilot informed ATC and requested a vector to the closest airport. He was able to keep the engine running by actuating the fuel primer knob, but the airplane would not maintain altitude. The pilot performed an emergency landing in an orange grove. The airplane touched down in soft terrain and nosed over. Investigation revealed a thick, slimy substance, black and brown in color, was found in the carburetor bowl drain plug, obstructing its fuel channel.
