I am having the same exact problem, went through everything 4 or 5 times and it does the same thing. Any help would be appreciated.

Make sure you remembered to put the black interruptor cup on the motor shaft and that it is pressed all the way on.

So that black cup is NOT to spin????

That black cap must turn with the motor shaft. The shutters must travel between the RPM sensor on that little circuit board or you will have the exact problem you describe in your first post.

well, I got it a little tighter...doesn't spin to the touch anymore...it is traveling between the RPM sensor...still same issue???? Shouls I take a washer or 2 off of the shaft and get it even tighter??

If you followed the instructions in the box you probably replaced the worm gear as well. Remove the black cap and loosen the coupler up on the end of the shaft. On the front of the motor, where the other end of the shaft pokes through, push the shaft back as far as it will go and hold it there while you tighten the coupler back up. Put the black cap back on and see what happens.

IT WORKS.....Thankyou SO MUCH, you saved me $ and taught me that perseverance is always wins...