1991 Johnson/Evinrude Models "EI" 40 thru 55 Service Manual, Page 81Get this manual
6If you suspect the anti-siphon valve, perform these tests Remove 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 test 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 leak8If your reading is less than in Hgand no bubbles are visible, move the clear hose to the output side of the in-line fuel filter Start engine and run at full throttle If bubbles appear, test in-line fuel filter If no bubbles appear, go to Step 99If no bubbles appear in Step 8, remove the clear hose and install 0-15 PSI (0-103 kPa) fuel pressure gauge between pump and carburetorsAvoid pulling "E.S1763" fuel line off fuel fittingsPush off wherever possibleWhen removing "E.S1763" fuel line from fittings, carefully cut the hose to avoid damaging the fittings10Start engine and run at 800 RPM in gear After 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 that PSI (21 kPa), test pulse limiter and Component Servicing, crankcase fittingRefer to this Section If pulse limiter and crankcase fitting are good and pumppressure is less than PSI (21 kPa), replace