On November 17, 2010, approximately 1940 central standard time, a Beech 35-33, N5481, was substantially damaged when it impacted trees following a loss of engine power near Roanoke, Texas. Night visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of 14 Code of Federal Regulations Part 91 without a flight plan. The pilot was not injured. The cross-country flight departed Jackson, Mississippi, and was en route to Roanoke, Texas. According to a written statement submitted by the pilot, while on base leg for runway 35 the engine "went to idle power". The pilot performed the emergency checklist but was unable to restore engine power. During the forced landing the airplane impacted several trees. The airplane's right wing separated from the fuselage, and the left wing was crushed aft and embedded into an adjacent tree. The airplane's salvage recovery team reported that the right main fuel tank contained 8 gallons of fuel and the right auxiliary fuel tank contained 1/2 gallon of fuel. The left main fuel tank contained 15 gallons of fuel and the left auxiliary fuel tank contained 1 quart of fuel. An engine test run was conducted while the motor was still attached to the airframe, utilizing an external fuel source attached to the left side fuel system. The engine started and accelerated to 2,400 rpm. A dark black smoke was observed from the exhaust system and the engine ran rough at full mixture. The engine ran smooth when leaned. Further examination of the engine's fuel delivery system revealed that the number five fuel nozzle, main filter screen, and fuel screen were full of contaminants. The source of the contaminants was not determined. The fuel system was placed on a test bench and the unit operated as designed. The leak rate on the metering unit return to the fuel pump was higher than normal. Additional examination revealed that the diaphragm on the manifold was not as pliable as a newer diaphragm; however, there were no cracks and no leaks noted.