I understand. I wondered this, also. The limit screws are fairly
stiff and I need to adjust them almost the exact amount of turns each
time (2+ turns). I'll look more closely and mark their positions to
see if vibrations are causing the trouble.

On Jan 31, 7:37 pm, "DerbyDad03" wrote:
Mark the position of your limit screws and see if vibration is causing
them to turn on their own.