On October 19, 1993, at 1350 Pacific daylight time, a Grumman G-164B, N7501K, lost engine power, hit a chain link fence, and ground looped while taking off from a privately owned airstrip near Arvin, California. The pilot was beginning a local visual flight rules aerial application flight conducted under Title 14 CFR Part 137. The airplane, operated by San Joaquin Helicopters, Delano, California, and the chain link fence sustained substantial damage. The certificated commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The pilot reported that during the takeoff roll the engine began to lose power and shake violently when it was about two-thirds down the 2300 foot long runway and started to shake violently. The pilot jettisoned the chemical load before exiting the runway environment and colliding with the fence. An engine examination was conducted on December 2, 1993, at the operators facility. Mr. Gregory Minarik, Aviation Safety Inspector, Federal Aviation Administration (FAA), Fresno [California] Flight Standards District Office, supervised the examination. Inspector Minarik reported that the examination disclosed no evidence of any pre-existing malfunctions or failures. (See Inspector Minarik's Engine Teardown Memorandum, herein this report, for further details of the examination).