hey there, first timer on forums so bear with me, I got a little stihl 021 at a yard sale a while back for like $25, 16 in bar, good chain, case and all, good freakin deal I thought. the guy didn't know if it ran so I just put a new spark plug in it and it fired up. I ran the saw a little while and it started getting weird on me, It will idle fine but acts like it starves for gas when you pull the throttle, hold the throttle and it'll die, if you pump the gas I can get it to rev up. I've messed with the carb settings, set them to factory, of course its got new gas and clean filter, fuel filter looks good, WHAT NEXT? compression low? maybe I just need to pull the carb apart and clean? What do you think?