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8-1-2 PILOT SYSTEM
The pilot system feeds the fuel to the engine during idling and low-speed operation.
/"l
The .fuel
is
fed through the main jet
to
the pilot jet, where it
is
metered, and mixed with the air metered
by the pilot air jet.
The fuel-air mixture is fed to the engine through the pilot outlet and the by-pass.
At
the idling speed, the fuel
is
mainly fed from the pilot outlet.
8-1-3
MAIN
SYSTEM
The main system feeds the fuel to the engine at medium-and high-speed operation.
The fuel
is
metered by the main jet and fed to the main nozzle. The air metered by the main air jet is
mixed with the fuel through the bleed holes in the main nozzle, and the mixture is atomized out of the
main bore. It
is
mixed again with the air taken through the air cleaner into an optimum fuel-air mixture,
which
is
supplied to the engine.
8-14
CHOKE
The choke may be used for easy start when engine
is
cold. When the engine is cranked with a closed
choke, the negative pressure applied to the main nozzle increases and draws more fuel accordingly this
starting up the engine more easily.
8-2
DISASSEMBLY AND REASSEMBLY
Apart from mechanical failures, most
of
carburetor troubles are caused by an incorrect mixing ratio,
which may arise mainly due to
a
clogged up air or fuel passage in jets,
or
fuel level variations.
In
order to
assure proper flow
of
air and fuel, the carburetor must be kept clean at a11 times. The carburetor
disassembly and reassembly procedures are as follows.
8-2-1 THROITLE SYSTEM
(1)
Remove the philips screw
(1)
and throttle valve
(2),
(2)
The spring
(4)
can be taken out by removing the
*
Be
careful not
to
damage the throttle valve rim.
and pull
out
the throttle shaft
(3).
throttle stop screw
(5).
8-2-2
CHOKE
SYSTEM
(1)
Remove the philips screw
(6)
and choke valve
(7),
and pull out the choke shaft
(8).
(2)
When reassembling the choke shaft, make sure that
the cutout in the choke valve faces the main air jet.
Meanwhile, when reassembling set the rings
(9)
and
(10)
at the right position.
8-2-3
PI
LOT SYSTEM
(1)
Remove
the
pilot jet
(ll),
using proper tools to
(2)
Reassembly
avoid damage to
it.
Tighten the pilot jet securely. Otherwise, the fuel
may leak, causing engine malfunction.
123
It
7%
u
\
21
-@
13*
18
0
12
"----&
Fig.
8-3
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48
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