On March 28, 1998, approximately 1730 central standard time, a Carter Long-EZ homebuilt airplane, N83LE, was substantially damaged during a forced landing following a partial loss of engine power near Lebanon, Oklahoma. The private pilot and the pilot-rated passenger received minor injuries. The airplane was registered to EZ Aviation of Dallas, Texas, and was being operated by the pilot under Title 14 CFR Part 91. No flight plan was filed and visual meteorological conditions prevailed for the personal flight that originated from the Addison Airport in Dallas about 1640. According to the FAA inspector who examined the accident site, the airplane landed to the north about two-thirds of the way down a 3,000 foot long grass airstrip. The airplane overran the north end of the strip, nosed over, and came to a stop in the inverted position in a wheat field. The canard, both wings, and both vertical stabilizers sustained structural damage. The fuel selector was found on the left tank position. The FAA inspector observed fuel leaking from the left wing tank fuel cap. When the airplane was placed back on its landing gear, the inspector drained approximately 1 cup of fluid from the left tank, which consisted of about 2 tablespoons of water and what appeared to be 100LL aviation fuel. The gascolator/ fuel screen bowl was removed and "it was discovered to be essentially full of water." No water was found in a fuel sample taken from the right fuel tank or in the fuel drained from the carburetor bowl. During a telephone interview conducted by the NTSB investigator-in-charge, the passenger, who held a private pilot certificate, reported that the airplane was washed and then refueled before the flight. He did not watch the pilot preflight the airplane. Approximately 40 minutes into the flight, the engine began "cutting out and then kicking back in." After flying for 5 to 8 minutes looking for a place to land, the pilot of another airplane flying with the accident airplane saw a grass strip. The passenger estimated the wind was from the south at 10 to 15 knots. According to the passenger, the pilot landed downwind, because landing into the wind would have meant hitting mobile homes at the south end of the strip in case of an overrun. The owner of the airplane reported to the FAA inspector that "when he left the airplane parked outside in Jonesbourgh, Arkansas, at an earlier date, it rained overnight, and he found considerable water in the fuel system the next day." Repeated attempts to obtain a completed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) were unsuccessful. According to FAA records, when the pilot's most recent medical certificate was issued on March 24, 1998, he reported that he had accumulated 750 total flight hours of which 30 hours were in the last 6 months.