Dave is correct – that is a bad bowl gasket. Your 28hp takes OMC/BRP carb kit 439074 – here’s a pic showing the correct gasket. There may be another issue with the carb but I’d start with getting the correct gasket.
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."