Section IV. CARBURETOR
184. Description
The carburetor is a down draft unit, incorporating a primary and secondary venturi. The main discharge tube is located in
one of the two supporting arms and 'terminates at the center of the secondary venturi. All air is taken from inside the air
intake. This balanced construction enables the carburetor to maintain correct air-fuel ratios even though the air cleaner
may become restricted. The accelerating pump and the power (or economizer) systems are controlled by engine manifold
vacuum. The accelerating pump system is vacuum operated. The accelerating pump instantly delivers fuel directly into
the air stream on sudden throttle openings. It also controls the volume of discharge of this fuel. The power jet controls the
additional fuel required for maximum power at wide-open throttle operation. It is called an economizer or a bypass jet in
some carburetors.
185. Carburetor Disassembly
a. Remove the carburetor (par. 78a).
b. With a file, make match marks on the choke bracket (2) and the air intake body (5) to aid in reassembling these
parts. Remove the five screws with lockwashers (4 and 9), raise the air intake body (5) until the gasket (12) can be
loosened, and lift the air intake body from the fuel bowl.
c. With the choke in the wide-open position, file off the end of the riveted fillister head screw (7). Remove this screw
(7) and the choke plate spring (8). Then remove the choke shaft and lever (13) so that the choke plate (6) can be lifted
from the air intake body. Remove the fillister head screw (14).
d. Remove the vent and idle well (11) and the well seal washer (10), using the fingers only. Remove the air intake
gasket (12), then remove the assembled pump (49), guide (50), spacer (51), and pump spring (52) from the fuel bowl.
e. Remove the check valve with jet (47) and the well seal washer (10). It may be necessary to use a small wire hook
to lift the well seal washer from the recess in the fuel bowl.
f. Remove as a group, the float (15), float axle (17), axle retainer plugs (16), and the needle portion of the fuel valve
and seat (19). Use the special tool, float axle lifter (par. 179) to do this. Insert the forked end of the float axle lifter into the
bowl and under the float axle (17). Use the edge of the bowl as a fulcrum to pry the axle and retainer plugs up out of the
fuel bowl.
g. Unscrew and remove the fuel valve seat (19) and fiber washer (20). Use the special tool, valve seat wrench
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