I have a 168 brushed. And for the life of me, I cannot adjust the throttle. Its a cable throttle and inside the controller a V shaped opening is pulled back to allow more light through the diode which determines the speed. But there is no spring or anything to put tension on the cable to put it back to "idle" when the twist throttle is not being turned. It seems like a spring should go there but there isnt one. And I might just add one. Has anyone else looked at this or worked on this before? Thanks