Mariner Mercury 105/140 JET, Service Manual, Page: 230 / 797

90-824052R3 JUNE 2002 FUEL SYSTEMS - 3C-23
Vapor Separator Fuel Delivery Test
Purpose: Verifying there is adequate fuel flow to the
electric fuel pump (through full RPM range)
will determine components in low pressure
fuel system are functioning correctly.
Procedure: STEP 1: Remove hose from intake
port of electric fuel pump and put discon-
nected end of hose in clean container.
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Results: If fuel flow is present, fuel is being delivered
to electric fuel pump. Go to high pressure flow
chart.
If fuel flow is not present, proceed to step 2.
STEP 2: Place emergency stop switch in OFF
position to prevent engine from starting. If
boat is not equipped with a emergency
stop switch, connect a jumper lead from
the BLACK/YELLOW terminal on the
switch box to engine ground.
STEP 3: Turn ignition key switch to “START” and
operate starter motor for 10 to 20
seconds.
STEP 4: Look for fuel flow from hose.
IN-LINE
FILTER
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Results: If low or no fuel flow is present following
inspection of in-line filter, perform Vapor
Separator Float Test.
Vapor Separator Float Test
Purpose: This test will indicate if float is stuck in the
up position.
NOTE: If float is stuck down vapor separator will over
flow causing a rich condition.
Procedure: If float is suspected of sticking in the up
position:
STEP 1: Remove fuel inlet hose from vapor
separator and put end of hose in clean
container.
STEP 2: Remove all spark plugs from engine to
prevent engine from starting.