On May 9, 2004, about 0835 mountain daylight time, an experimental 2003 Nash Kitfox II, N308KF, sustained substantial damage following a loss of engine power, off airport landing and subsequent nose down in an open field near Broadview, Montana. The airplane is owned by the pilot and was being operated as a visual flight rules (VFR) personal/pleasure flight under the provisions of 14, CFR Part 91, when the accident occurred. The airline transport pilot sustained minor injuries in the accident. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Billings, Montana, approximately 40 minutes prior to the accident. During a telephone conversation with the National Transportation Safety Board IIC on May 10, the pilot reported that the airplane experienced a sudden unexpected loss of engine power while in a normal flight configuration. The pilot restarted the engine, however it quit a second time and he initiated a forced landing to a nearby field. The pilot reported that just before touchdown, the airplane pitched nose down and impacted terrain at a 40 degree angle. The airplane nosed over resulting in substantial damage to the forward section of the fuselage and the tail. The pilot also stated that he landed with a tailwind. In a written statement dated May 14, the pilot reported the loss of engine power was "characteristic" of fuel starvation, however, the airplane had approximately 20 gallons of fuel on board and the fuel valve was in the open position. During the post accident examination of the wreckage, by personnel from the Helena, Montana, FSDO, fuel system continuity was established, however, it was noted that fuel was only present from the supply tank to the firewall mounted fuel pump. No fuel was observed in the system between the pneumatic fuel pump and the engine. The airplane was equipped with a Mikuni pneumatic fuel pump, mounted on the firewall in the vertical position. The airplane was not equipped with an emergency or standby fuel pump.