Bought my son a Cen GST 7.7 for christmas. Were having a blast. but, I think were stuck in first gear. We've adjusted the screws for second and third gear, but I think were still stuck. How do I know the gears are shifting and how do we adjust properly.

hey lyleha try setting the truck off the ground listen too the engine sound also if your truck looks as its going 40 mph its shifting through all the gears