WELL I GOT MY DECATHLON OUT YESTERDAY FOR THE FIRST TIME. ENGINE RAN GREAT ON THE GROUND. I TAXIIED UP AND DOWN THE RUNWAY SEVERAL TIMES AND IT RAN FLAWLESSLY, I SPED UP THEN CUT THE THROTTLE WITH NO PROBLEMS AT ALL. PROBLEMS STARTED ONCE IT GOT INTO THE AIR AND UP TO SPEED. THE ENGINE WOULD FOUR STROKE.. AS THEY CALL IT. I BROUGHT IT DOWN AND DID SOME MINOR ADJUSTMENTS TO THE CARB WITH THE SAME RESULT IN THE AIR. I BELIEVE WHATS HAPPENING IS THE CARB INTAKE IS LOCATED OUTSIDE OF THE COWL, I THINK THE AIR GOING OVER IT IS SUCKING OUT THE OXYGEN MAKING IT RUN RICH IN THE AIR CAUSING THE 4 STROKING. IT HAS SOMETHING LIKE A VELOCITY STACK ON IT BUT ITS REALLY JUST A STRAIGHT TUBE OFF THE ORIGINAL CARB INLET. WOULD IT HELP IF I CUT ONE SIDE DOWN AND FACED IT INTO THE WIND SO AS TO CUP THE AIR FORCING IT INTO THE CARB NOT ALLOWING THE CARB TO RUN RICH? OR DOES ANYONE HAVE ANY OTHER IDEAS ON WHAT I CAN DO TO FIX THE PROBLEM? THANKS