BB1 and 245S carburetors have the throttle lever riveted on the shaft. BB1A, 245SA, and 289S carburetors have throttle levers that are adjustable on the shaft to facilitate installation where variations occur in the length of the accelerator or hand throttle rods.
BB1D, 245SD, and 289SD carburetors have die-cast lower bodies.
Early production 245SD, BB1D, and 289SD used float lever pins and plug assemblies inserted from the outside of the body.
Later production (starting October 1st, 1945 and designated as H-45 on inspection tag) uses float pin and pin retainer in slot in bowl.