The trimmer head does not rotate when I open the throttle. What do I do?

There can be several reasons for the trimmer head not rotating when you open the throttle. First, check that the trimmer head is fitted correctly, and is not jammed. Next, check that the spindle is still firmly attached to the machine.

If this does not solve the problem, look for the following: 1. Broken coupling. 2. The spindle has sheared. 3. The angle gear has broken.