On March 7, 2018, about 1230 central daylight time, a Cessna 150M airplane, N66786, experienced a partial loss of engine power after takeoff and impacted terrain during a forced landing to a field near the Alfred C 'Bubba' Thomas Airport (T69), Sinton, Texas. The pilot and one passenger were not injured, and the airplane sustained substantial damage to the engine mount. The airplane was owned and operated by the pilot under the provisions of the Title 14 Code of Federal Regulations Part 91 as a personal flight. Day visual meteorological conditions prevailed at the time of the accident, which was not operated on a flight plan. The flight departed T69 about 1130 on a local flight. The pilot reported that he conducted a local flight and returned to land at T69 and executed a touch-and-go landing to runway 32. After touching down and taking off again for another touch-and-go, the airplane's engine experienced a partial loss of engine power near the end of the runway. He was unable to gain altitude, so he turned to the right and landed in an open field. During the forced landing the airplane's engine mount was bent; otherwise the airplane appeared to be undamaged. The pilot reported that he examined the airplane's carburetor and found that was full of carbon, and that the exhaust pipe was pitch black from carbon buildup. He stated that the carburetor was unable to properly regulate the fuel/air mixture due to excessive carbon buildup, corrosion in and on the main nozzle, and basic wear and tear, which caused the engine to flood and experience a partial loss of engine power. He stated that a review of the airplane's maintenance logbook showed that the carburetor had not been rebuilt since it was installed in 1974. The pilot stated that a new rebuilt carburetor was installed on the engine and it now runs fine. The airplane recently had an annual maintenance inspection and he reported that "everything that may have caused the engine problem checked out okay."