Incline Motor Behavior

Hi, I have two 1/121HP incline motors from two different treadmills. It has a 18uF external capacitor which seems to be fine when I checked it with the multimeter. The incline won't go all the way up and is stops at 20%. What kind of electrical/mechanical evaluation can I perform to determine root cause?

I have another incline motor of the same origin, that did not stop when it reached max incline, and kept on going until the inner screw of the shaft broke off.

Any suggestions would be much appreciated.

Thanks