as you throttle up, about halfway you will notice the light turn red. this indicates that you are now running constant RPM. as you increase the throttle beyond the halfway point, motor RPM remains the same, but blade pitch continues to change.

Your motor problem could be the lower bushing has failed. this happened to me once, basically the bushing/bearing behind the pinion wears out and the pinion and shaft now can wobble a bit. you need a new motor if so.