On April 21, 1997, about 1300 central daylight time, a Grumman G-164B, N6601Q, registered to Payne's Flying Service, Inc., operating as a 14 CFR Part 137 aerial application flight, experienced a partial loss of engine power during initial takeoff climb in the vicinity of Ackerman, Mississippi, and crashed during a forced landing. Visual meteorological conditions prevailed and no flight plan was filed. The airplane sustained substantial damage. The commercial pilot reported no injuries. The flight originated from Ackerman, Mississippi, about 3 minutes before the accident. The pilot stated he was "hot refueled", (refueled with the engine running), and did not drain the fuel sumps before departing. While on climbout at about 400 feet he experienced a noticeable decrease in engine torque and engine noise. The airplane began to lose attitude. He made a May Day call on company frequency. There were no suitable landing areas available, and a forced landing was made into the trees and terrain. According to the President of Payne's Flying Service, Inc., they were working out of a remote site in Newton, Mississippi, and were refueling the airplane from a tanker trailer with four compartments. Refueling is started from the first compartment aft to the rear compartment. The tanker trailer should be parked on level ground. If the nose of the tanker is low, it will catch the water and dirt and transfer it to the first compartment. The tanker trailer was moved and when relocated, it was not level. During the same time period, several weather fronts passed through with heavy rain, and the tanker trailer was resupplied with fuel. On the day of the accident, the auger truck that was supplying N6601Q with fuel, had to be refueled. It obtained its fuel from the tanker trailer. N6601Q was the first airplane to be refueled by the auger truck. After the accident, the pilot informed him that he thought he had a fuel problem. He instructed company personnel to check the tanker trailer, auger truck, and the other company airplane. All fuel systems were contaminated. Examination of the tanker trailer revealed that the incorrect fuel filter had been installed which was provided by the filter supplier in Jackson, Mississippi. Examination of the airplane fuel system revealed contaminated fuel in the primary fuel filter and fuel container at the engine fire wall.