14
enlarges the pump element forcing fuel out of its cavity.
This pressurized fuel acts against the outlet flap valve,
opening it, allowing a head of pressurized fuel to be
transmitted to the inlet needle and seat port. The inlet
valve is pressed against the inlet port, sealing it so
that pressurized fuel does not escape back into the
fuel tank and lines.
The flap valves are located between the cover and
into the rod a complete 2 turns.
Then position the extended end of the choke rod spring
on the idle adjustment rod and align the spring with
the choke rod holes in the bracket. Press the choke
rod through the bracket and spring with the link attaching
hole toward the carburetor side.
Install the choke shaft link in the rod, then install the
other end in the choke lever.
Install the control bracket to the carburetor, but do
not tighten screw completely.
Tighten the setscrew to secure the rod to the idle
adjustment cable. The rod should turn about a half
turn before contacting the extended end of the choke
spring.
It is important that the idle adjustment screw be one
full turn from closed, and that the rod setscrew be
down (6 o'clock position) when connecting the rod and
coil.
Tighten the control bracket screw. Pull the choke rod
to assure that the choke shutter closes.
BRACKET
IDLE ADJUST ROD
IDLE
ADJUST
NEEDLE
AND SPRING
LINK
THROTTLE
LEVER POST
CHOKE ROD
ROD STOP
SPRING
IF CURLED OR FRAYED REPLACE
COVER
INLET FLAP
OUTLET FLAP
STRAINER
FROM THE 6 O'CLOCK POSITION,
THE ROD WILL TURN ABOUT 1/2 TURN
EACH WAY BEFORE BEING STOPPED
BY THE SPRING ROD
ABOUT 1/2 TURN
6 O'CLOCK
POSITION
GASKET
FUEL
INLET
OUTLET
FLAP
VALVE
INLET FLAP
VALVE
FUEL PUMP
ELEMENT INFLATED
gasket. Make sure the flaps are in good condition and
the strainer is not clogged or damaged. Replace as
necessary. Make sure the cover is not warped; check
by laying on a flat surface. If warped, replace. If not
warped severely, it can be refaced using a hard surface
and emery cloth. Notches on the carburetor body insure
that the gasket, valve, and cover are positioned on
the body correctly. When tightening screws, snug bottom
screw, then top screw and torque to 6-8 in. lbs.
OUTBOARD CONTROL PANEL.
Install the idle
adjustment rod into the bracket then turn the setscrew
OUTLET
FLAP
VALVE
INLET FLAP
VALVE
FUEL
INLET
FUEL PUMP
ELEMENT DEFLATED
As the engine's piston, moves upward, a partial vacuum
is created in the crankcase, which collapses the fuel
pump element in the carburetor. On the outside of the
element, suction opens the inlet flap drawing a supply
of fuel from the tank and lines into the cavity created
by the deflating pump element. Suction pulls the outlet
flap closed, sealing the outlet port so that fuel isnt
pulled from the area of the inlet needle and seat.
On the downward stroke of the piston, crankcase pressure
Summary of Contents for AH520 -
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