Are you looking specifically for Johnson TD-20 or something more inclusive with all brands?
I have digital copies of the Johnson 3rd and 10th edition. Neither are dated. They
have specifications going way back, but most of the service procedures appear
to be for motors in the 50’s, and early 60’s.
This website has some good data on the TD type carbs, etc.
http://pochefamily.org/outboard/
Assuming there were actually a Johnson 4th thru 9th edition as well, did each
include all the data from the previous edition, and hence, each edition got thicker?
What year did Edition 1 come out? Inquiring minds want to know!