On April 15, 1996, at 1015 central daylight time, a Cessna 177, N3322T, was destroyed by fire after an aborted takeoff. The accident occurred at Harrisburg-Raleigh Airport, near Harrisburg, Illinois. The private pilot and his pilot rated passenger reported no injuries. The personal 14 CFR Part 91 flight was on the takeoff roll on runway 24 (4,004' X 75' dry/asphalt), when the engine experienced a loss of power. The pilot reported that the airplane was brought to a stop off the runway when smoke was seen. He and his passenger evacuated the airplane and determined that it was on fire. The fire continued and the airplane was destroyed. The local flight was originating at the time of the accident. The pilot stated that when power was applied for takeoff, the engine did not appear to develop full power. He said that he then reduced the power to idle and the airplane was directed into a turnaround area. He said that at that time the engine quit and smoke was visible coming out of the cowling. He indicated that he pulled the mixture to idle cutoff and turned the master switch off; after which, he and his passenger exited the airplane. The pilot did not know how the fire originated. An inspector from the Federal Aviation Administration examined the airplane. He stated that examination of the engine compartment failed to reveal the source of the fire. The fuel system sustained substantial damage from the ground fire and was compromised to an extent to prevent determination of the source of the fire. He said that the fire was fed by a supply of aviation fuel on the airplane. The inspector said the primary electrical system was burned and no evidence of a fire source was evident.