Those are small drive screws holding the serial plate on the transom clamp. You can just drive them out from the back side of the clamp with a small diameter punch. Replacement fasteners are available at McMaster Carr or Fastenal. Just do a search for “drive screws” on their websites.
Bob
1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
1982 Evinrude 25hp
“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."
