The rubber wedge fills the space between bottom of tank and top of spark plug cover. I believe they are being reproduced.
KB-1 was entry level Special, KB-1A was Standard and KB-3 Was top of line Deluxe. KB-3 had two screw transom clamp while the Special and Standard models had the single screw fabricated steel transom clamp.
Photos show 1940 and a 1941 single powerhead
Front view of KB-3
Top and front view of a KB-1A with a mixed tan… top of rewind KB-3 and bottom from a KB-1A which does not have the chin because it las a rope start without cowl. Possibly factory mix, but, I picked it up as parts.
