IF someone has put self-adjusters on it, you will need to 'push out' the ratchet plate to turn the star wheel in. An icepick works great, you just have to put it thru the backing plate slot & push outwards, hopefully you have it on the plate, if so, you'll feel some 'spring resistance' after making contact with it. Then just push it outwards towards the wheel about 1/4". Then, while maintaining that, with your other hand, de-adjust the star wheel. Don't worry, it's easier done than said.
Doug