With only 2 fuel lines (in and out), it sounds like your motor was converted to a fuel pump system in place of the factory original 3-line system that used a pressure type fuel tank. This conversion required capping or plugging the original air supply line on the intake manifold, so verify that it has been plugged (see pic attached). You can buy a replacement 2-line fuel pump at a number of places – do a search for Sierra 18-7350.
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."