WELL I HAD THE DECATHLON OUT AGAIN TODAY FINALLY.. I MADE A SMALL HOLE IN THE FRONT OF MY VELOCITY STACK FACED INTO THE WIND. RUNS FLAWLESSLY NOW. DOES NOT 4 STROKE AT ALL NOW THROUGHOUT THE WHOLE THROTTLE RANGE. I MUST SAY THIS 40CC ENGINE I HAVE IS A REAL BEAST COMING OUT OF A CHAIN SAW. IT HAS ELECTRONIC IGNITION AND IM USING A 20X8 PROP. WITH A PLANE THATS 16-17 POUNDS IT HAULS IT AROUND WITH AUTHORITY. ACCORDING TO THE THRUST HP PROGRAM IM GETTING 24 POUNDS OF THRUST AT 3.6 HORSEPOWER. NOW IF I CAN FIGURE OUT MY GLITCH PROBLEM IVE BEEN HAVING DURING FLIGHT EVERYTHING WILL BE FINE .. THANKS FOR ALL THE INPUT.. AT LEAST MY ENGINE TROUBLES ARE BEHIND ME..