That would typically be caused by a faulty controller or throttle and because the throttle was replaced and the problem was not fixed, that points towards the controller causing the problem.
It is very common for an electric scooter controller to lock into the full power on position when it overheats and burns out. You are definitely on the right track with replacing the controller and that should solve the problem.
The fuse burning out is most likely caused by the power being applied to the motor all at once instead of gradually as the throttle is being engaged. However if the fuse continues to burn out after the new controller is installed then it might be the wrong Amp rating of fuse.
Thank you. I took the controller apart and noticed some burn marks on the motherboard. Seems like that will be the problem.
I recently purchased my son a 1000 Watt scooter. It keeps burning the fuse. When I put a new fuse in and connect the battery pack, the scooter lurches forward and burns the fuse. I have replaced the ignition switch and the throttle and it didn't fix the problem. I have ordered and am waiting for a new control module. I have also inspected the unit thoroughly for loose and frayed wires and haven't found any. Any suggestions?