1998 Johnson Evinrude "EC" 40 thru 55 2-Cylinder Service Manual, P/N 520206, Page 74Get this manual
This chart determines the condition of the fuel pump portion and air motor portion of the VRO pump External fuel leak? Connect gearcase pressure tester to VRO pulse hose fittingPressurize to 15 PSI(Air motor piston travels full stroke to the right, poppet valve opens, and piston returns full stroke to leftBoth pressure and vacuum chambers are pressurized to 15 PSI Does pump hold pressure?
INSTALL FUEL CHAMBER O-RING, FUEL OUTLET FITTING O-RING, OR FUEL INLET FITTING O-RING Slowly pump gearcase testerInspect for escaping air Does pump click several times with each stroke of tester?
Hold pump in normal running positionCover fuel outlet, Rapidly remove pressure hose from pulse fitting Pump should not clickDid pump click? Air motor cover is cracked or leaking, or vacuum port O-ring is leakingREPAIR LEAK, REPLACE VACUUM PORT O-RING, OR REPLACE AIR MOTOR COVER
I Is air leaking from fuel outlet?