1998 Johnson Evinrude EC 50 thru 70 HP 3-Cylinder Service Manual, Page 71Get 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 fitting Pressurize 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?
External fuel leak?
INSTALL FUEL CHAMBER aRINGFUEL OUTLET FIT TlNG ORING, 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 leaking REPAIR LEAK, REPLACE VACUUM PORT O-RINGOR REPLACE AIR MOTOR COVER Is air leaking from fuel outlet?
Locate external leakREPAIR LEAK ;REPLACE INTERMEDIATE HOUSING
Wait secondsUncover fuel outlet Pump should clickDid pump click?