1971 Johnson 4HP Outboard Motors Service Manual, Page 23Get this manual
CLEANING, INSPECTION, AND REPAIR FUEL LINE, SCREEN AND NIPPLE ASSEMBLY Disconnect the fuel hose from the tankSee "Clamps" in paragraph "Hose and Primer Assembly", Section 3Remove the fuel line, screen and nipple assemblySee Figure 3-19Inspect screen for varnish deposits and remove with Accessory E;:ngine Cleaner
r-NIPPLE
Figure 3-21Removing Hose
!LINE SCREEN
Figure 3-19Fuel Line, Screen and Nipple VENT ASSEMBLY vent assembly acts as one way valveIt should admit air into the tank but prevent fumes from escapingcheck operation the valve, alternately blow into the valve and draw outAir should enter but not escapeValve components can serviced unscrewing from tankSee Figure 3-20
Figure 3-22Attaching Hose
_ _VALVE