People like to play with the carb adjustments when the saw won't run or won't rev cleanly or won't rev properly - it seldom turns out well - often you inherit a saw that has been so tinkered-with that it won't run even with good spark & compression
Based on my experience, here are some thoughts
(1) Empty all the old gas out of the tank, put in a wee bit of new clean gas and shake it around to give it a flush then tip that out too
(2) Get a bit of bent wire and fish out the fuel filter and blow it clean with compressed air then fill the tank with fresh 2-stroke mix - maybe 25:1 or 32:1 with that old saw? If it should be 40:1 a bit extra won't hurt short-term. Use good quality 2-stroke oil such as Husqvarna or Motul - something that is designed for chainsaws not lawnmowers and that says "suitable for 2% or 50:1 mix" on the label
(3) Remove the aircleaner (it'll need a good clean before it goes back on), open the choke and tip half a teaspoon of gas down the carb. Close the choke, turn it on and pull a few times. It should splutter, start, run briefly and then stall. Try it a couple times. If that doesn't work, probably tinkering with the carb won't fix it
If that does work, then . . .
(4) Carb settings: There will be two screws probably side-by-side on one side of the carb. High speed mixture and low speed mixture. Also somewhere there'll be an idle speed device - probably as a throttle stop? With a bit of luck on the plastic housing there will be two screwdriver holes marked maybe "H" and "L" (high and low) or similar? It'll be obvious that you need a small flat-bladed screwdriver
Blow the whole area clean with compressed air and screw both screws in gently until they stop. Then screw them out again one and a quarter turns (probably one and an eighth is gonna be closer to ideal but one and a quarter will get you started)
At those settings the saw should start and run and rev (but probably not rev very cleanly) and it might idle of the throttle stop is OK
If that stuff works OK you should google "chainsaw carb tuning" or similar to get it just right
The aircleaner needs to be spot on clean and in good shape too
Good luck