If your not privy on saw stuff bring it into a dealer for a chain sharpening and a tune.
If you want to attempt some of this on your own, get yourself a full chisel chain if it dosent have one already, crank the ooler to the max setting and get yourself a husky/poulan tuning driver.
Setting the high low on these saws is sooo much easier with the 8$ Driver which isnt sold in stores, amazon sells them.
But if you really want to remove the adjuster limiters (these prevent you from turning the screw more than half a turn in any direction with a regular slotted driver) you need to pull the carb. The limiters are metal and you need to keep them to retain tension on the screws themselves so they dont back out due to engine vibrations. You will then need to remove the screws by dicking around with the limiter caps and turning the screws out until they come out completely. Dremel off the limiter boss and re assemble.
Like i said just get the proper tuning driver .
Or bring it in and pay the 20-30 bucks for the dealer to tune it for you