Advertisement
CARBURETOR-BBD
1
'h
I N C H
14-25
OF
CYLINDER)
-
_
I
_
_
-
Fig. 3-Removing
or Installing Step-up Piston
(Fig.
4).
(13) Remove the venturi cluster screws, then lift
the venturi cluster and gaskets up and away from
main body, as shown in (Fig. 5). Discard the gaskets.
Do not remove the idle orifice tubes or main vent
tubes from the cluster.
They can be cleaned in a
solvent and dried with compressed air.
(14) Invert the carburetor and drop out the accel-
erator pump discharge and intake check balls.
(15) Remove the idle mixture adjusting screws and
springs from the throttle body.
(16) Remove the screws that attach the throttle
body to the main body. Separate the bodies.
(17) Test the freeness of the choke mechanism in
the air horn. The choke shaft must float free to operate
correctly. If the choke shaft sticks in the bearings, or
appears to be gummed from deposits in the air horn,
a thorough cleaning will be required.
The carburetor now has been disassembled into
three main units, namely, the air horn, main body and
throttle body and the component parts of each disas-
sembled as far as necessary for cleaning and inspec-
tion.
MAll
Fig. 5-Removing
or Installing Venturi Cluster
It is usually not advisable to remove the throttle
shaft or valves from the throttle body, unless wear or
damage necessitates the installation of new parts.
INSPECTION AND ASSEMBLY
Throttle
Body
(1) Check the throttle shaft for excessive wear in
the throttle body. (If wear is extreme, it is recom-
mended that the throttle body assembly be replaced
rather than installing a new shaft in the old body).
During manufacture, the location of the idle trans-
fer port and the spark advance control ports to the
throttle valve, is carefully established for one partic-
ular assembly. (See Fig. 6.)
If a new shaft should be installed in an old, worn
throttle body,
it
would be very unlikely that the orig-
inal relationship of the ports to the valves would be
obtained. Changing the relationship of the valves to
the ports would adversely affect normal car operation
between the speeds of 15 and 30 miles per hour. How-
ever, if
it
has been determined that a new shaft or
valves is to be installed, adhere to the following in-
structions:
(2)
Mark the position of the throttle valves to the
shaft, then slide the valves out of the bores.
IDLE TRANSFER PORTS SPARK ADVANCE
h
CONTROL PORT
Fig. &Removing
or Installing M a i n Metering Jets
Fig. &Ports
in Relation
to
Throttle Valves
Hide quick links:
Advertisement
