Article 1009 - Carburetor Loading During Engine Warm-Up 4300-4V Carburetor

TSB #61 - March 10, 1967
(1967 Falcon and Mustang 289-4V Engine Equipped Units Built Prior to Approximately March 15, 1967)


Customer complaints of carburetor loading during the engine warm-up period on subject units may be caused by improper choke response to engine temperature. These units built prior to approximately March 15, 1967, incorporate a model "C0" or "BW" choke cover and related choke adjustments. Units built after this date employ a revised model "BX" choke cover with revised specifications as follows:
Choke Cover"BX"
(C7AZ-9848-C, Class B)
Choke Cover SettingIndex
Choke Pull Down Clearance.109 (7/64) Inch
Fast Idle Cam Clearance.080 (5/64) Inch
Fast Idle Speed1350 RPH

Use the following procedure to apply this revised choke cover and related specifications to a previously built complaint unit:

Choke Pull Down Clearance
    I. Remove and discard model "CO" or "BW" choke cover.
    II. Bend a .036 inch diameter wire gauge at a 90 degree angle approximately 1/8 inch from the end and insert this end into the slot in the choke piston bore (Illus. S1188).
    III. Rotate the choke lever counter-wise (rearward) until the slot in the top of the choke piston is snug against the wire gauge.
    IV. Holding the choke lever in this position, measure the clearance between the lower (front) edge of the choke plate and the air horn wall. To adjust this clearance, carefully bend the lever arm on the choke shaft. CAUTION: Excessive Bending Will Break This Lever Arm.

Fast Idle Cam Clearance
    I. Position the fast idle speed adjusting screw at the top of the kickdown (middle) step on the fast idle cam.
    II. With the fast idle cam in this position, rotate the choke lever counterclockwise (rearward). Measure the fast idle cam clearance between the lower (front) edge of the choke plate and the air horn wall. Adjust this clearance with the adjustment screw in the plastic fast idle cam. (Illus. S1189).

Fast Idle Speed
    I. Connect a tachometer to the engine.
    II. With the engine at operating temperature, position the fast idle adjusting screw at the top of the kick down (middle) step on the fast idle cam.
    III. Turn the fast idle adjusting screw to achieve the specified engine RPM. (Illus. S1189)
    NOTE: These adjustment procedures are also outlined on page 10-9 of the 1967 Ford Preliminary Maintenance Manual

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WARRANTY STATUS - REIMBURSABLE
Oper: SP-9510-E-67
Time: 0.4 hrs.

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