Circumstances
The pilot entered the downwind leg of the traffic pattern, selected carburetor heat on, reduced engine rpm to 1,300, and left the flaps up. After completing the base and final portions of the pattern, the pilot was unable to land the airplane and initiated a go-around. He advanced the throttle, but the engine did not respond. He then retarded the throttle and advanced it a second time, again with no response. The airplane subsequently impacted trees at the far end of the runway.
Engine Examination
With the engine still attached to the airplane, an engine run was performed. No anomalies were observed during the test.
Placard Information
The airplane lacked a required placard that should have read: 'DO NOT OPEN THROTTLE RAPIDLY (IDLE TO FULL THROTTLE, 2 SECONDS MINIMUM)'. This placard was intended to alert pilots to potential power interruptions and acceleration hang-ups that can result from abrupt throttle movements.