2004 SR Johnson 2-stroke 40, 50HP Service Manual, Page 144Get this manual
FUEL SYSTEM FUEL SYSTEM TESTS
FUEL SYSTEM TESTS
CAUTION
START outboard and run at FULL THROTTLE for at least two minutesMonitor clear vinyl hose for the presence of airAir bubbles indicate faulty hose, connection, or fuel tank pick-upRepair, if necessary, before proceedingThere should be no air or vapor bubbles visible in the clear hoseThe maximum inlet fuel vacuum must not exceed inHg(13.5 kPa) at the fuel inlet of the pump under any operating conditions (IDLE to WOT)A higher vacuum indicates an excessive restriction in the fuel supplyRepair as neededRefer to FUEL SYSTEM REQUIREMENTS on p49
To prevent accidental starting while servicing propeller, twist and remove all spark plug leads
Install the proper test propeller and put the outboard in suitable test tank
IMPORTANT: To avoid damaging the fittings,
push hoses off fittingsDO NOT pullIf pushing will not separate hose from fitting, carefully cut the hose along its length and peel it backStart the outboard and allow it to reach normal operating temperatureStop the outboard