Did you check the tires? sitting for years can leave flat spots, I have that same saw,I haven't taken it apart no need,how loose is the pulley? Is there a keyway in the shaft? has the key way worn out like gotten wider a sloppy key will cause problems! that is what I find on fan motors a lot!(I'm an hvac man) then I get a wider key stock and file to fit, or as stated before good old 'JB weld' and make the shaft fatter , and sand to fit, or fill key way and let a greased! key set in the slot till hard! be creative grease the set screws! they may need to come out! that really is a nice saw! I looked for a year to find mine don't give up to soon you'll get right we have faith in you man!! another trick, is to take a good prick punch and hit the shaft at 12 o'clock 3 o'clock 6 o'clock and 9 o'clock the divet will displace just enough steel to tighten the pulley fit, make sure that you grease the shaft good when you put it back, you may need to remove it! JEFFW