So basically there was a small spring that I put around the rope on the inside of the mount, in the cavity where the stopper is. The spring was between the stopper and the mount itself.
Unfortunately, the spring provided so much friction that by manually twisting the rope, it would actually spin the mount. I had to use 100% of the weights to let the mount even have a chance of overcoming the friction of the spring.
So I'll have to try again with no spring and less weight.