Carter AFB carburetor accelerator pump. Leather pump.  Please be sure to compare the measurements from the picture.
Match your carburetor number with the list provided.

Carter AFB Carburetor Identification

2506S, 2507S, 2625S, 2740S, 2751S, 2767S, 2768S, 2789S, 2799S, 2800S, 2819S, 2820S, 2840S, 2859S, 2877S, 2897S, 2906S, 2955S, 2975S, 2976S, 2981S, 2982S, 3010S, 3012S, 3088S, 3089S, 3221S, 3258S, 3259S, 3266S, 3269S, 3270S, 3297S, 3298S, 3310S, 3345S, 3361S, 3362S, 3452S, 3460S, 3461S, 3499S, 3503S, 3578S, 3579S, 3593S, 3633S, 3634S, 3635S, 3645S, 3646S, 3660S, 3665S, 3720S, 3721S, 3783S, 3804S, 3826S, 3827S, 3921S, 3922S, 3923S, 3924S, 3925S, 3963S, 4030S, 4033S, 4034S, 4035S, 4037S, 4041S, 4053S, 4054S, 4055S, 4056S, 4059S, 4060S, 4061S, 4133S, 4179S, 4180S, 4181S, 4242S, 4243S, 4244S, 4245S, 4246S, 4248S, 4310S, 4318S, 4331S, 4332S, 4344S, 4393S, 4394S, 4413S, 4453S, 6310S