On Friday afternoon, October 8, 1993, at about 1600 Pacific daylight time, a Cessna 172M, N9932Q, operated by Pavco Flight Center, impacted terrain and nosed over four miles east of Longbranch, Washington, during an emergency forced landing. There was no flight plan filed for the local training flight, which was conducted under 14 CFR 91 in visual meteorological conditions, that took off at Tacoma, Washington at 1520. The certified flight instructor and the private pilot were not injured in the accident. The aircraft was substantially damaged. There was no fire. Flight instructor Dawson reported he was conducting a pre- rental aircraft check-out for private pilot Perez when he reduced the throttle to simulate an engine failure at 2300 feet MSL. The instructor pilot said that carburetor heat was used during the descent, but that he only "cleared the throttle" once. A surface weather observation taken about ten minutes prior to the accident, at a location six miles from the accident site, recorded a temperature of 62 degrees and a dewpoint of 46 degrees. Both pilots said that the engine did not respond when the private pilot initiated a recovery from the simulated forced landing about 1000 feet MSL. He indicated he took the controls, and attempted to recover engine power, which was not successful. He said he initiated an emergency forced landing in an open field. After touchdown on the soft terrain, the aircraft nosed over. The engine was inspected and successfully test run after the accident. No failed components or functional anomalies were discovered.