1990 Johnson Evinrude "ES" 9.9 thru 30 Service Manual, P/N 507871, Page 64Get this manual
Fuel Tank Testing fuel system to service which could leak liquid or vaporized fuelIgnition of this leakage could result in fire or explosionWhenever fuel tank or line has been serviced or has had parts disassembled, the unit must be tested to ensure that the repaired or reassembled portion will not leak or emit fumesSimply adding fuel to the tank and checking for leakage is not an adequate test, as leakage or fumes may occur only when the tank's contents have been pressurizedAs examples, pressurization can occur when the tank is left in sunlight, or when the fuel is agitated, as might occur during transport ill
J Omitting the tank pressure test may result in returning a
Tools needed are an air pressure gauge and OMC Fuel Tank Pressure Test Adapter PIN 389945 compressed air supply is also needed