Sequence of Events
While climbing after takeoff, the engine stopped and then restarted. The pilot turned the aircraft to the north, after which the engine stopped again. The pilot then allowed the aircraft to stall, and it subsequently crashed into a wheat field.
Aircraft and Fuel Information
The aircraft had a Supplemental Type Certificate (STC) for the use of automotive gasoline (auto gas). Examination of the fuel system revealed that the fuel contained contaminants, including water and rust. The fuel lines were found to have dried. The carburetor was equipped with a composite float, and the spark plugs and carburetor throat were covered with soot.
Maintenance and Standards
According to the report, composite floats are no longer manufactured by the original manufacturer, and the Airworthiness Directive (AD) requiring their installation has been rescinded. Multiple sources, including an FAA Advisory Circular, the FAA Accident Prevention Program, a Piper service bulletin, and Lycoming Flyer, have highlighted the lack of uniform standards for automotive gasoline and the problems arising from inadequate standards. The FAA has stated that auto gas can allow carburetor ice to form at higher temperatures.