On June 17, 1993, at 2145 Alaska daylight time, a wheel equipped Stinson 108-2 airplane, N318C, registered to and operated by the Pilot-in-Command, crashed during the initial climb after takeoff from Dry Creek Airstrip, Dry Creek, Alaska. The personal flight, operating under 14 CFR Part 91, was departing Dry Creek for a local flight. No flight plan was filed and visual meteorological conditions prevailed. There were no injuries to the Pilot-in- Command or the passenger and the airplane was substantially damaged. According to the Pilot-in-Command, the ground run was sluggish because of the soft runway conditions. He used runway 25 which runs uphill 10 feet over the 3200 foot length. The airplane lifted off at mid field and the Pilot had to lower the nose to gain airspeed. The airplane cleared the 20 to 25 foot high trees at the end of the runway and again the Pilot lowered the nose to gain airspeed. He stated there was no perceptible acceleration. He turned to the right away from rising terrain and continued to mush into the trees. The right wing struck some trees and the airplane turned clockwise and crashed to the ground. The Pilot stated he did not believe the airplane's engine was producing full power. Federal Aviation Administration, Aviation Safety Inspector examined the airplane and the engine and found no reason for a loss in power. Furthermore, the ground run of the engine did not show any problems. The FAA Inspector stated the Pilot told him the engine was running smoothly during the takeoff. He stated that during the runup the engine was developing 2200 RPM. The airplane manual states that 2350 is the maximum RPM. The airplane was equipped with a cruise propeller and the pilot stated that the engine would normally develop 2200 RPM at the beginning of the takeoff and increase to 2300 RPM as the airspeed increased. The Pilot stated he was using a mixture of half aviation fuel and half automotive fuel.