1993 Johnson Evinrude "ET" 60 degrees LV Service Manual, P/N 508286, Page 53Get this manual
6If you suspect the anti-siphon valve, perform these testsRemove anti-siphon valve from fuel tank, and install adaptors and clear hose as shown Fill clear hose with water until "X" dimension is 20 in(500 mm)Water must not run through valve Increase water level until "X" dimension is 25 in (630 mm)Water must begin to run through valve before reaching 25 in(630 mm) Replace the anti-siphon valve if your results vary7If your reading is less than inHg and air bubbles are visible in the clear hose, check entire boat fuel system for air leaksRemember, an air leak into fuel supply system might not create visible fuel leak8'If your reading is less than inHg and no bubbles are visible, move the clear hose to the output side of the fuel distribution manifold Start engine and run it at full throttle If air bubbles appear, test vacuum switchRefer to Vacuum Switch Servicing, this section9If no bubbles appeared in Step 8, remove the clear hose and install 0-15 PSI (0-103 kPa) fuel pressure gauge between pump and carburetors10Start engine and run it at 800 RPM, in gearAfter fuel pressure stabilizes, the pressure gauge must not indicate less than PSI (21 kPa) when held level with VRO hose fitting If pressure is less than PSI (21 kPa), test pulse hose and crankcase fitting Refer to VRO Component Servicing, this section If pulse hose and crankcase fitting are good and pressure is less than PSI (21 kPa), replace pump Transpare nt Hose Adaptors Anti -Siphon Val ve