On August 19, 1995, about 0820 central daylight time, a Ronsrans R 12, N800RK, collided with a fence and then the ground, during takeoff at Clanton, Alabama. The registered ultralight aircraft was operated under the provisions of 14 CFR Part 91, and visual flight rules. A flight plan was not filed for the personal flight. The private pilot and his passenger were seriously injured, and the ultralight was substantially damaged. The flight was originating at the time of the accident. The FAA inspector who visited the accident site reported that the pilot lost control during his departure and collided with the ground. According to the pilot, the engine was producing 100 RPM less than normal on takeoff, and he stated, "the plane didn't want to climb or takeoff." He decided to make a precautionary landing, selected a suitable location, and pulled back the throttle. The pilot realized that there was a fence below, and gave the engine full power, but the aircraft stalled and collided with the fence. An examination of the ultralight revealed that the flight controls were connected and operable. The American Motor Works (AMW) engine did not run during the engine examination due to the impact damage, however, the compression check was satisfactory. The FAA inspector closely examined the spark plugs and he found a heavy coat of fuel and oil mixture on them. He also stated, "It appears the carburetor was set excessively rich, and or the fuel oil mixture had been mixed incorrectly."