On March 19, 1997, at 0709 mountain standard time, a Piper PA-28-140B, N98150, operated by Bob Gates Aviation and doing business as The Pilot Center, was substantially damaged when it struck a post during an emergency landing at Fort Collins, Colorado. The private pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under Title 14 CFR Part 91. The flight originated at Fort Collins-Fort Collins Downtown Airpark minutes before the accident. The pilot said that shortly after taking off from runway 11, the engine lost power. He "pumped the throttle" and the "engine sputtered twice and quit again." The pilot then made a emergency landing 1 mile south of the airport in the Prospect Ponds Natural Wildlife Area. During the landing roll, the pilot was able to avoid a concrete picnic table but the left wing struck a trail marker post, shearing off and driving the landing gear through the wing. According to the operator, the engine was functionally tested later that day and it operated normally. They carburetor was disassembled and inspected the following morning. The accelerator pump operated normally, and the metal float moved freely. There was no evidence that the float may have shifted and was binding against the housing. There were no obstructions in the one-piece venturi. The pilot said he had experience in the Piper PA-28-180, but had very few hours in the PA-28-140. Fuel selector operation on both types of airplanes is identical. The pilot said he was thoroughly familiar with properly selecting a fuel tank with the fuel selector. The pilot said he leaned the mixture at 1,800 rpm (revolutions per minute) prior to takeoff. According to Textron Lycoming, the mixture should be leaned at full (takeoff) power. If the mixture is leaned at a lower power setting, the mixture will enrich as power is applied.