Well I got the carb screw in and now I have a new problem. When I hit the throttle the engine revs like it's on a test stand but the wheels weren't moving, when it was doing this all I had to do was tighten the wheel nut and it would fix but now it doesn't work. The slipper is tight and everything else is tight. What could be the problem? I was thinking it is either the output yolks or the diff.