1987 Johnson/Evinrude CU Outboards 35A thru 55 Service Manual, Page 82Get this manual
Fuel Tank I!J tune-up or major repairDram tank at an outdoor
location, away from all possible sources of ignitionA drain screw is provided in the fuel tank upper housingClean the tank by flushing with clear gasoline or solventPrimer pump, screens, etc may be inspected and cleaned as described belowRefill the tank with the correct fuel mixtureCleaning, and Repair
Drain and flush
least .once year, and at every
If the tank or hose appears to be leaking fuel or fumes, pressure test tank and hose assembly before doing any disassemblyClean the fuel tank and inspect for rust or leakageReplace tank if badly rusted or if it has developed leaks in the metal bodythese materials are sold as being suitable for fuel tank repairGenerally, these materials are sold for repairing automotive fuel tanks and are not suitable for portable marine tanks which are subjected to much higher pressure and vacuum conditionUsing fuel tank which has been patched could result in fuel leakageIgnition of this leakage could result in fire or explosion