1998 Johnson Evinrude "EC" 90, 100C, 105C, 115, 150, 150C, 175 60 deg. LV Service Manual, P/N 520210, Page 72Get this manual
This chart determines the condition of the fuel pump portion and air motor portion of the VRO pumpConnect 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.I Does pump hold pressure?
External fuel leak?
INSTALL FUEL CHAMBER O-RING, FUEL OUTLET FITTING O-RING, OR FUEL INLET FITTING O-RING Hold pump in normal running position Cover fuel outlet, Rapidly remove pressure hose from pulse fitting Pump should not clickDid pump click?
Slowly pump gearcase testerInspect for escaping air Does pump click several times with each stroke of tester?
Air motor cover is cracked or leaking, or vacuum port O-ring is leakingREPAIR LEAK, REPLACE VACUUM PORT O-RINGOR REPLACE AIR MOTOR COVER
I Is air leaking from fuel outlet?
Fuel piston diaphragm or flapper valve leaking, or missing outlet fitting O-ringINSTALL FUEL PISTON AND DIAPHRAGM KIT, CHECK DRING Wait secondsUncover fuel outlet Pump should clickDid pump clic