My son’s quad has a flat spot when the throttle is opened quickly from idle to wide open (slamming the throttle from closed to open). It idles fine and runs great. There is no pause when throttling slowly. I know the pilot/slow jet controls idle, but what else could it be? I took the carb apart and it was spotless. I went ahead and cleaned it out with carb cleaner and compressed air anyway. I also messed around with the air/fuel mixture and still cannot get rid of the dead spot. The machine is jetted correctly, sparkplug is good, air filter, etc. Any thoughts? Thanks for any suggestions.