During flight at 13,000 ft MSL, the engine began losing power. The aircraft was vectored toward the Prospect Airport near Tiller, Oregon. However, about two minutes later, all engine power was lost. During a forced landing, the aircraft struck a dead coniferous tree beside a logging road. The impact with the tree occurred at 117 ft AGL. Ground impact occurred 162 ft from the tree in an upright and relatively flat attitude. The elevation of the crash site was about 3000 ft MSL. No mechanical failure of the engine was evident. During examination of the fuel system, the right fuel cap was secured to the fuel cell, but was difficult to remove and reinstall due to binding and improper seating. Rust was noted around the fuel cap and fuel cell filler neck, both above and below of where the rubber grommet was seated. Several pieces of granular ice were removed from the right fuel cell. Water was found in both the fuel filter bowl and the fuel flow distributor.