On May 7, 1994, at 1630 central daylight time, a Grumman G-164A, N9682, was destroyed during a forced landing near El Campo, Texas. The commercial pilot was seriously injured. Visual meteorological conditions prevailed for the aerial application flight. The pilot reported that during the takeoff initial climb, after turning crosswind, the engine started to lose power. During the emergency descent the airplane struck power lines, and control was lost. The pilot attempted to jettison his chemical load for the forced landing. The pilot further reported that the airplane came to rest inverted, and was destroyed by a post-impact fire. An examination of the engine revealed no mechanical failures that could have caused the loss of power. However, testing of the magnetos revealed that one was weak and the other magneto was arcing inside its case.