Okay then. That is the same model that I have, just a bit earlier... mine was marketed for the professional thinner from what I understand. Gonna talk to Roger. Will let you know what else I find out.
Stihl TK-10 Carb Par# - 4112 120 0611 so I searched again and loookee what I found! OEM STIHL TK CARBURETOR CARB (OLD 4112 SERIES) FS 80, 80AV, 80AVR STRING TRIMMER
It ain't cheap but hey, this saw is worth the price. Looks like a NOS part on top of that - new in the box.
While talking to Roger he said to me that almost any 25cc to 30cc Walbr carburetor should work provided the bolts line up. Might have to mickey mouse aka redo the linkages for the throttle but that shouldn't be a big deal. However if you get the one above.. it is a simple bolt on. Since I only need the bulb - I will pass on this and leave it to you as you need it more than I do. Roger is going to give me a hand to see what we can do with my Stihl over the winter. Oh yeah, he also said that there are still a few parts for the engine available in the Stihl pipeline but they are not cheap of course.
I hope this helps. Let me know what you do/decide.
If anyone has an extra bulb they aren't doing anything with I would appreciate it