If the cable adjustment isn't tight it'll spin on ya and either get too far out or in(prob in), try twisting the botton instead of spinning it.
See if it feels like it catches then loosens up, if it does, you will have to pull the unit out and adjust your fork guide, it could also have lost the c-clip off the little shaft or your fork could be broken, you can either have one mad eor order one from Loc-rite or whatever.
Let me know if you still can't figure it out, I would pull the unit off first, also check for wear on the cable and make sure its not broken any where along the way and taht you have good action inside with the fork.