Evinrude 4906B 4HP 1969 Owner's Manual page 149

4-58 FUEL
The primer pump is operated
buretor is full of fuel.
started. Once the engine is operating,
at idle speed, pressurized
intake manifold through a check valve and
the hose to the fuel tank.
increased inside the fuel tank, the fuel is
forced through the fuel hose to the carbure-
tor.
Each tank should build and retain
following pressures:
Model CD
Model AD
Model QD
Model FD
Model RD
When the engine is shut down and the
fuel hose is disconnected
the fuel tank cap should be opened slightly
to allow the air pressure
escape. It is not a good practice
the tank to remain pressurized.
Any engine equipped with this pressuriz-
ed fuel system can be updated by installing
a fuel pump. The cost of replacing
pressurized-type fuel tank actually
the cost involved in making the conversion.
The necessary work involves drilling a hole
in the bypass cover to mount the pump and
provide the pump with vacuum from one of
Fuel and air pressure lines attached
type fuel tank through the double connector.
line has a rib extending its [ull. length.
until the car-
The engine is then
even
air is fed from the
As pressure is
the
2 to 4-1/2 lbs.
2 to 5 lbs.
2 to 5 lbs,
2 to 5-1/2 lbs.
2 to 4-1/2 lbs,
from the engine,
in the tank to
to allow
the
exceeds
to a pressure-
The fuel
the cylinders. Installation
the carburetor is not a difficult or expensive
task.
The accompanying
shows the two hoses connected
tank. The hose on the left transfers
the carburetor and the hose on the right is
the air pressure line.
ing the fuel line, the fuel hose has a rib
extending its full length from the tank to
the carburetor. The primer
dearly shown in the illustration.
DISASSEMBLING
WARNING
TAKE EXTREME
with the fuel tank, because highly flamable
fumes are present and the danger of fire or
explosion is present.
NO SMOKING or open flame in the work
area. Clean the tank in the out-of-doors.
1-
Check to be sure the knob on the
pump shaft is able to rotate
The knob is secured
cotter pin. If the knob does not turn during
operation, the diaphragm
be damaged or ruptured.
Explana tion
The following description of pump opera-
tion may be helpful in explaining how dam-
age to the diaphragm
failure of the button to turn.
When a person operates
action is not in a straight
The natural tendancy is to turn the thumb or
hand while operating the plunger.
is connected directly
Therefore, if the knob fails to turn,
shaft will be torn away from the diaphragm.
of new hoses to
illustration clearly
to the fuel
fuel to
To assist in identify-
pump is also
CARE during work
Demand and observe
on the shaft.
to the shaft with a
in the pump will
may be caused by
the pump, the
down direction.
The shaft
to the diaphragm.
the