Article 939 - Momentary Engine Hesitation on Light Throttle Acceleration

TSB #50 - November 4, 1966
(1967 390-2V Thermactor Automatic Transmission Units Built Prior to Approximately Oct. 1, 1966)


Customers with subject units may complain of occasional momentary engine hesitation during light throttle acceleration. This complaint on units with proper tune-up specifications is caused by a lean fuel mixture during acceleration. The following procedure should be used to resolve this customer complaint:
    1. Perform a normal service diagnosis to assure that the problem is not caused by improper distributor dwell, ignition timing or related tune-up adjustments.
    2. If correction is not obtained, raise the carburetor fuel level by decreasing the wet fuel level setting from 7/8 to 25/32 inch.
The fuel level modification applies to carburetor models C7AF-Z and C7OF-M. Revised carburetor models C7AF-BE and C7OF-AF incorporate this modification.

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