On September 11, 1997, at 1620 hours Hawaiian standard time, a Cessna 150L, N18503, nosed over during a forced landing about 9 miles south of the Hilo, Hawaii, airport. The aircraft sustained substantial damage. Of the two occupants, one sustained serious injuries, and the other incurred minor injuries. The nonstop inter-island personal flight originated in Honolulu, Hawaii, on the day of the accident and was going to terminate in Hilo. Visual meteorological conditions prevailed for the route of flight and a VFR flight plan was opened at 1454. The pilots stated that they had rented the uninsured aircraft from a mechanic at the Honolulu Airport. They stated that they did the preflight and the aircraft "was good to go." Neither pilot stated in their written reports how fuel quantity was verified before departure or how much fuel was on board. The first pilot stated only that the owner had told them that the aircraft had already been fueled. The pilots reported that about 10 miles out from the Hilo airport "the engine began to die." They contacted the FAA Air Traffic Control facility at Hilo and declared an emergency and told them that they were "going down." The second pilot reported that at that time he took the controls to avoid heading for a road that was "covered with wires," and "stalled the plane just as we touched down, but the grass was so tall that it snagged the front of the plane and flipped it over." The plane came to rest inverted. The first pilot, seated in the right seat, possessed a commercial airplane single engine land and multiengine land certificate with instrument privileges. The second pilot, seated in the left seat, possessed an airline transport pilot certificate for multiengine aircraft, and a commercial certificate for airplane single engine land. The second pilot also holds a certified flight instructor certificate for single and multiengine aircraft, as well as for instrument. FAA inspectors from the Honolulu Flight Standards District Office (FSDO) responded to the accident site and examined the aircraft. No fuel was found in the tanks or around the aircraft. They also reported that the vegetation under and around the tanks did not show signs of fuel spillage. The hobbs meter showed the duration of the flight to be 3.1 hours. According to the Cessna Pilot Operating Handbook (POH), the 150L model holds a total of 26 gallons, with 22.5 useable gallons, and burns approximately 6 gallons per hour. The second pilot reported to the aircraft owner that they "were flying at about 110 MPH, they were not at altitude, and they did little leaning." The POH for the model 150L was reviewed. According to the performance charts, at 2,500 feet the power setting which results in a TAS of 110 mph is 92 percent power. The fuel consumption rate for that power setting is approximately 7 gallons per hour and the maximum endurance would be 3.2 hours. The engine was inspected and run at the Honolulu airport following recovery of the aircraft. The fuel lines were found to be intact and the spark plugs were in good condition. There were no noted discrepancies.