REBUILD KIT, CARBURETOR, MIKUNI BST36, Full list of parts contained in the kit: Japanese-made float needle & fuel screw o-ring, genuine Mikuni float bowl gasket, vacuum port cap, cold start slide shank seal & fuel feed tee seal, needle seat o-ring, cold start enrichment feed pipe o-ring, slide guide o-ring, vacuum port o-ring, felt throttle shaft seal, two stainless steel flat hexalobular throttle blade screws and instructions. All o-rings in this kit are FKM. NBR vs. FKM o-rings