ROCHESTER CARBURETORS

Bulletin 9C-305 15 October 1954

CHEVROLET
1953-54-55 TRUCK — 235 Cubic Inch Engine
CARBURETOR 7004468
CARBURETOR ADJUSTMENTS
FLOAT LEVEL ADJUSTMENT (Use Tool M-250)
With air horn fully assembled, air horn gasket in position and assembly inverted (Figure 1) :
1.  Place float level gauge, M-250, in position as shown, with gauge projection inserted in dis­charge nozzle.
2.  Carefully bend float lip vertically so that each float just touches top portion of gauge. If one float is higher than the other, slightly bend the float arms to bring them into alignment.
3.  To prevent sides of floats from rubbing inside of bowl bend float arms horizontally so that each float is centered in the gauge.
4.  Tilt assembly 90° each side and check that floats do not touch gauge.
tmp52C-1.jpg
FIGURE 1
FLOAT DROP ADJUSTMENT (Use Tool BT-93)
To insure sufficient entry of fuel into the bowl under high speed operation it is necessary to check and adjust the float drop as shown in Figure 2. With the air horn held upright and the floats suspended freely, carefully bend the drop tang at the rear of the float assembly so that the bottom of the float is 1-3/4" below the air horn gasket surface. Use float drop setting gauge BT-93. Install air horn assembly to bowl and tighten cover screws evenly and securely.
tmp52C-2.jpg
FIGURE 2
CARBURETOR SPECIFICATIONS
TUNE-UP SPECIFICATIONS
Dimensions; S.A.E. Flange Size—1-1/2" Primary Venturi— 1-11/32" Secondary Venturi—19/32 Nozzle Restriction—.161"

Identification: Main Metering Jet— #58

 

Square Approach Air Horn Gasket—-Stamped 4468

 

Flange Face—Stamped 4468

Pump Discharge Hole:  .031"

Power Restriction: .043 '

Spark Plug Gap - .035
Breaker Point Gap - .018"
Cam Dwell - 38 - 45
Ignition Timing - 2 A.T.D.C.
Tappet Clearance - INT. .006" EXH. .020" (HOT)
Idling R.P.M. - 475
Note—Float Level Gauge M-250, and Float Drop Setting Gauge BT-93 ale available through U.M.S. Distributors,

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