Event
During the takeoff climb, at approximately 100 feet above ground level, the pilot experienced a partial loss of engine power. This necessitated a forced landing in a soft, wet potato field. The pilot had time to switch fuel tanks and magnetos before touchdown, but the power loss remained constant. Upon landing, the aircraft flipped over onto its back.
The pilot reported that the pre-takeoff engine run-up and magneto check had been normal.
Engine Examination
An examination of the engine revealed that 5 of the 8 spark plugs were lead fouled. Among those, three were completely shorted out and two sparked intermittently. Two of the malfunctioning plugs were on the same cylinder.