CARBURETOR (Cont'd)
Description (Cont'd)
The enrichment system does the following functions [A):
This system provides
additional fuel to the main metering
system during high-speed
large torque operation. The
diaphragm
is
actuated by intake manifold vacuum and
spring to open or
close the fuel feed line.
During partial throttle operation, the manifold vacuum is
applied to the vacuum chamber and acts
on
the
diaphragm to
close the valve against spring force.
When the
throttle is opened, manifold vacuum
decreases. This
allows the diaphragm spring to open the
valve. Now, more fuel from the float chamber can flow
through the valve into the enrichment jet.
The accelerator-pump system does the
following
functions [B):
Rapid opening of the
throttle, requires a sudden demand
for
additional fuel.
Fuel
from the inlet check valve is sent tot he pump nozzle
through the outlet check valve by movement of the
diaphragm. The diaphragm is pushed by the pump
lever
linked
to the throttle valve.
When the engine
is
decelerated, the diaphragm is pushed
back by the spring and the chamber is refilled with
fuel.
Added Sept. 90
-7D-~
,
"
"
Valve
741, 742, 743, 743DS Bobcat Loader
Service Manual
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