On December 4, 1993, at 1045 eastern standard time, a Cessna 150, N4092J was substantially damaged following a collision with terrain near Griffin, Georgia. Neither the flight instructor nor the student pilot were injured in the accident. The aircraft was being operated under 14 CFR Part 91 by the pilot. Visual meteorological conditions existed at the time, and no flight plan had been filed for the local, instructional flight. The flight departed Griffin, Georgia, at about 0930. The pilot stated that while maneuvering for a 45 degree entry into the traffic pattern, the engine lost power and that attempts to restart the airplane engine were unsuccessful. The pilot then force landed the airplane in an open field and intentionally swerved and struck the left wing on a tree to avoid colliding with a house at the end of the field. Post accident investigation of the airplane revealed that the fuel tank vent was completely blocked by a dirt dobber nest. The nest was located at the first 90 degree bend of the vent approximately 3 inches from the end of the vent. Examination of the engine revealed no evidence of mechanical failure and the engine was successfully run after the accident.