1981 Johnson/Evinrude 4HP Outboards Service Manual, Page 29Get this manual
bRemove starter as described in Section 7cDisconnect fuel line at filter and plugdRemove retainers attaching fuel tank to mounting bracketSee Figure 3-20Lift off fuel tank cInspect fuel tankIf it leaks, replace tankdFlush tank with clear gasoline or solvent once year
INSTALLATION OF FUEL TANK
aInstall fuel tank and attach retainersSee Figure 3-20bReconnect fuel linecI nstall starter as described in Section 7dRun motor in test tank and check for leaks