Subject: Primary Fuel Inlet Float Needle Sticking Closed -
Model and Year: All Holley Carburetor Equipped Engines
Source: Chevrolet Technical Service Bulletin
Bulletin Number: DR #66-38, Section VIm
Date: July 7, 1966
TO: ALL CHEVROLET DEALERS
Stalling may occur on 327, 396 and 427 cu. in. engines equipped with Holley carburetor models 4160 or 4150 (except the Holley carburetor with center inlet on Corvettes). This may result from the primary fuel inlet float needle sticking in its seat after several hours "soak".
To prevent this condition, a new primary inlet needle was released for production March 28, 1966. The new needle has a clip (see sketch) which attaches to the float to assist in unseating the inlet needle. Carburetors have this production change may be identified by a date code stamped under the Chevrolet part number on the main body, i.e., "635" (6 - 1966; 3- March; 5 - 5th week) or later.
To take care of this problem in the field, the following parts were released for service June 27, 1966.
3905844 - Needle Unit - Carburetor Float
3905843 - Float Assembly
3852476 - Spring Carburetor Float
These parts should be installed as a set using the procedure outlined on page 2.
NEEDLE AND SEAT ASSEMBLY INSTALLATION PROCEDURE
1. Remove air cleaner.
2. Drain fuel from primary bowl.
3. Disconnect fuel line and remove primary bowl and metering block.
4. Remove float, splash shield, and needle and seat.
5. Reverse Steps 1-4 to install new needled, float and spring.
6. Install tachometer and set idle speed and fuel mixture.
Article ID: 1204
Created: April 29, 2015
Last Updated: April 29, 2015
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article/1966-corvette-service-bulletin-holley-carburetors-primary-fuel-inlet-float-needle-sticking-closed-1204.html