Choke Base Shaft Measurement

[Harry S.]

Good day, I'm trying to rebuild my AFB 3461S Choke. The choke base, number on the part, is 170-786. The choke base shaft, number on the part, is 14-583. My problem is the choke base shaft is too short, mine measures .666. I think is should be closer to .733. If anyone has their choke apart can you take a measurement for me? The part circled in red.

Choke Base Shaft.jpg

[Duke W.]

Re: Choke Base Shaft Measurement

I don't recognize that part. There is an AFB exploded view in the '63 Corvette Shop Manual. Can you tell us what item number identifies that part?

Duke

[Harry S.]

Re: Choke Base Shaft Measurement

Duke, the part circled in red. In the Shop Manual, it's part 34 in the WCFB blow-out. Probably the same 34 for an AFB.

IMG_4524.jpg

[Duke W.]

Re: Choke Base Shaft Measurement

I've got a 3461S in a box, but before I spend the time to find it I want to verify what part you're talking about. The AFB and WCFB are totally different.

I assume you have a 1963 Corvette Shop Manual. If you do look at page 6M-9 Fig. 20. It looks to me that you are talking about item #16. Is that correct and if so are you looking for the overall length of that part?

Duke

[Harry S.]

Re: Choke Base Shaft Measurement

I've got a 3461S in a box, but before I spend the time to find it I want to verify what part you're talking about. The AFB and WCFB are totally different.

I assume you have a 1963 Corvette Shop Manual. If you do look at page 6M-9 Fig. 20. It looks to me that you are talking about item #16. Is that correct and if so are you looking for the overall length of that part?

Duke

Duke, yes item 16.

Thanks

[Duke W.]

Re: Choke Base Shaft Measurement

I couldn't get a caliper on it without some disassembly, which I do not want to do, so I eyeballed with a ruler from the center of the shaft that goes into the choke housing to the hole that holds the link to the choke valve, and it appears to be right on 9/16".

This was on the original 3461S from my SWC, code CB3. I rebuilt it at least a couple of times, but installed and new 3721S back in the seventies keeping the original for posterity.

The biggest issue with these AFBs is the choke vacuum break piston gets dirty and sticky. I think that lousy OE foam air filter was the culprit because it allowed oil and dirt through, and a quality cellulose filter goes a long way to keeping it clean.

Also all AFB owners should note that tiny O-ring (item 17 in the exploded view from the '63 Corvette Shop Manual) between the choke housing and carb main body. That seals the clean air passage between the two parts. The design continuously pulls air from the air horn, through the tube in the exhaust manifold and then to the choke housing to operate the thermostatic spring, and if that seal is absent ambient and dirt will leak in causing degradation of choke function.

Duke

[Harry S.]

Re: Choke Base Shaft Measurement

Thanks Duke. 9/16 = .563. I already know that .666 is too short, then so is 9/16. I'll keep up the search,

Cheers

[Duke W.]

Re: Choke Base Shaft Measurement

I guess I gave you the wrong measurement. It occurs to me that you want the length of the shaft that's part of the choke piston outer lever . The only way to measure that is to remove the choke housing and shaft to measure.

Sorry... hope you can find someone with a disassembled AFB to measure.


Duke