I can’t tell for sure what’s happening in your picture but there is a retaining screw in the middle of the reed plate that needs to be removed. I can’t tell if you removed that screw or not because it’s covered up with some kind of gunk. If not already removed, that screw needs to come out to get the reed plate off. See attached markup of your picture.
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."