Circumstances:
The pilot said the preflight engine run-up was normal, although the engine seemed to run roughly with a slight RPM drop when carburettor heat was applied. A take-off was commenced but the pilot did not think engine performance was normal. After becoming airborne the engine ran roughly and lost power. The throttle was closed, and the aircraft was landed straight ahead on the strip remaining. However, the aircraft overran the strip end and collided with a fence. The pilot reported that wasps had nested in the intake ducting whilst the aircraft had been idle and uncovered during the previous few days. The nest had apparently dislodged during the preflight run-up causing eventual power loss after take-off. This accident was not the subject of an on-scene investigation.
