You could try Cat...part # 4H3349
or
Try this source....don't know anything about them.
My info says its a Zenith # C85-116
Their number has an S on the end...don't know what significance that has.
http://www.russellsnewoldparts.com/CARBURETORFLOATS.html
or
Try a Zenith Carburetor dealer.
Thanks! How about rebuilding?