What is the purpose of the magnet on the choke plate?

[KULTULZ]

I have the '64 shop manual (an original) and it says nothing about starting procedure.

Starting procedure will be described in the Owners Manual.

I was just conveying why the setting is called for.

[Yadkin]

OK I think I have a clue about this magnet. Or more mystery about my carburetor, I'm not sure which one.

According to the GP Sorenson instruction sheet for the 4100 F4, there are three different automatic chokes, '61 and earlier, '62-4, and '64 and later. None of the diagrams show the magnet.

For the '64, Sorensen says the choke pull-down is adjusted by a nylon not attached to the lever on the choke shaft, essentially changing the length of a control rod. My rod is a fixed length, just like the earlier chokes. But I don't have the adjusting screws shown on the '62-3; mine has to be adjusted per the '61.

Sorensen has instructions to adjust the magnet just as John has described, and that diagram shows the non-adjustable rod.

My carb #C4SF B "matches" what was installed in 1964, and my tag matches the stamped number on the base plate of the main body.

[KULTULZ]

Your carburetor is correct-

C4SF-B
C4SZ 9510-A
MPC 9510 Parts List 17Q
Magnet- Choke Plate C2SZ 9E585-A

There were several different choke designs as well as carb asm deviations. This is why it is so important to have that ASM. I.D. NO.

[Yadkin]

What is "asm"?

[KULTULZ]

ASSEMBLY

As In Assembly I.D. No.

[davidmij]

WOW! No wonder I had such a hard time getting my carb set up and running half decent. I changed the top plate from my existing 67 LTD 390 and put it on a 1969 Mustang carb that I used because the secondary vacuum pickup tube had broken on the old one. I bought the second carb for $40 for parts. The one has the plastic adjustable choke lever, the other doesn't. Amazing how many little changes they made year to year.

[Yadkin]

Not only year to year but possibly mid-year and rebuild kits sometimes have parts that have to be substituted in order to make other parts work.

For instance on my 64 Bird 390 the vacuum secondary diaphragm is "male", and the steel lever that acts on it is "female". Even the kit instructions don't know which one I'm supposed to have; you have to remove the cover to see. Many parts manufacturers only make the "female" diaphragm and supply a "male" nylon lever to replace the OEM steel "female" lever.

A replacement male diaphragm is much more expensive, if you can find one. I have discovered a way to convert a replacement female diaphragm to a male, by using a short #6 machine screw and threading it into the hole. That way I can use the OEM lever and the carb looks original on the outside.

Here's a picture of it showing the outside of the diaphragm and the OEM lever. I powder coated the steel parts to mimic cadmium plating.

[davidmij]

I ran into that too Steve. I think it was my original carb on my 352 in my 59 T-bird. I modified it with a screw as well. Mikes carburetors has all the right parts and kits. They seem to be a little more expensive with a standard rebuild kit, but they can get you ALL the correct parts. See their rebuild video in the technical resource section.

Dave J

[Yadkin]

Yeah I've bought one from Mikes before. I think it was $30, while a female was ten. Six months later, a different car, different carb and I ordered from a cheaper site and ended up with a female part. Stuck a screw in and lucked out.