The adjuster you linked is an inline type. It's basically a turnbuckle of sorts. Turning the whole thing does absolutely nothing You have to turn the central barrel while holding one end (or both) so it doesn't turn also. Usually friction against the housing holds it for you and turning the middle is all it takes, but if the threads are dry or corroded, the thread friction may be more than the end friction so you need to take charge.

Yes, there is no stop per se. At one end it bottoms out and you can't go farther, but at the other end, you can continue until you run out of thread and the part disengages. If you go too far and disengage, it's not too hard to line it up and get it started again, but it does take a bit of conscious effort.