[https://www.ifixit.com/User/2557873/cpleafs|'''++cpleafs++'''] since we have no idea what you are looking at, pictures would help tremendously. Use this guide [guide|21499] for that. Focus on the 4X$ model and the engine/transmission in particular. If it moves without load(kid) but not with load (kid), it is possible that this is a bad clutch/transmission or a bad carb/ valve adjustment etc. We need more information on the engine as well. Since you said that “but it sounds like it wants too. “ I assume that it does not stall, sputter or bog out. That would lead me to a drivetrain issue.