You are getting a lot of air turbulence at the top opening of the scoop. The carb will not function in all that pressure and turbulent air. The air must enter the carb as smooth and straight as possible to properly mix the gas and air. There is a lot of turbulent air coming off the hood and into the large open scoop. If you cannot use a taller scoop, then the the "thunder bolt" air intake system should work. Just my 2 cents.