Evinrude E-tec 75 HP Service Manual page 167

Lift Pump Vacuum Test
Confirm fuel supply to the fuel lift pump.
Temporarily install a vacuum gauge, T-fitting, and
8 in. (20.3 cm) of clear vinyl hose between the fuel
supply hose and fuel lift pump (inlet). Secure con-
nections with tie straps to prevent fuel or air leaks.
IMPORTANT:
Do not use fuel primer bulb, man-
ual fuel primer, or electric fuel pump primer to
restart outboard. A positive pressure in the fuel
supply could damage some vacuum gauges.
START outboard and run at FULL THROTTLE for
at least two minutes. Monitor clear vinyl hose for
the presence of air. Air bubbles indicate a faulty
hose, connection, or fuel tank pick-up. Repair, if
necessary, before proceeding.
There should be no air or vapor bubbles visible in
the clear hose. The maximum inlet fuel vacuum
should not exceed 4 in. Hg. (13.5 kPa) at the inlet
to the fuel lift pump under any operating condi-
tions (IDLE to WOT).
A higher vacuum indicates an excessive restric-
tion in the fuel supply. Repair as needed. Refer to
Fuel System Requirements on p. 39 for fuel sup-
ply component requirements.
Lift Pump Diaphragm Test
Perform this test only if a damaged pump is sus-
pected. This test does not confirm the perfor-
mance of internal fuel pump check valves.
Remove the pulse hose from the crankcase fitting.
Apply 15 psi (103 kPa) to the pulse hose of the
pump. Replace lift pump if pump fails to hold pres-
sure.
1
1. Pulse fitting
Anti-Siphon Valve Test
Remove anti-siphon valve from fuel tank. Install
adapter fittings and a 36 in. (91.4 cm) length of
clear hose to the inlet side (tank end) of valve.
3
000243
2
1. Anti-siphon valve
2. Adapter fitting
3. Clear hose
Fill clear hose with water to a height of 20 in. (500
mm). Water must NOT flow through valve. An
occasional drip is acceptable. Replace valve if
water drips continuously.
Increase height of water to 25 in. (630 mm). Water
should flow through valve as water level reaches
25 in. (630 mm). Replace the anti-siphon valve if
test results are different.
FUEL SYSTEM
FUEL COMPONENT TESTS
20 in. (500 mm)
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