When OMC computerized there parts inventory in 1958 many of these odd numbers were given 306xxx and 307xxx numbers. Parts books from the late ’50s to mid ’60s reflect these changes. Parts with low sales which were considered old and/or obsolete were simply dropped from the parts books. When BRP took over OMC they added a leading zero to avoid conflict with there existing part numbers. Thus Evinrudes 43X123 and Johnsons 43-123 became 307583 needle valve packing. Unfortunately I could not find a listing for 23-241. . . 😥
