I just bought and installed a 48cc engine on my bike. I finished the intallation at work and took it home last night with everything seemingly working good. But when I went to show my kids, the engine only raced full throttle. I can move the throttle on the handlebar and hear things moving inside the carb but it makes no difference. I can move the idle screw from one extreme to the other with no difference. just full tilt. I watched youtube videos on how to adjust these with the throttle cable so I did exactly what they said but it changed nothing. I put duct tape around the expansion slots on the carburetor mounting flange to seal any air leaks but it made no difference. any ideas why this would be?