Originally Posted by
genejockey
If it were ONLY the limit screw, it wouldn't screw up your indexing. But if it's ONLY your cable tension, you could end up with it not only shifting like crap, but also unable to get into the largest cog.
As far as how to do it, I like "Free to Cycle" on YouTube. He has a number of videos on setup and adjustment of derailleurs and such.
sounds like tension then.