There are any number of possibilities. All I know is that this saw is in mint condition, used very little from all appearances. And it seems that I have hijacked Kshansen's thread. Sorry about that. Don't know if it can be moved to my original thread in what's on your bench or another on Tillotson Carbs.I haven't worked on that model Tillotson carb or that kind of saw but i wonder is there any chance the original carb was replaced with another model / variant Tillotson that was actually not the correct carb for that saw at some point?