Carter AVS Sticking Primary Shaft-'69 GTX 440

Two years ago I rebuilt the original 440 in my GTX. Since it is a numbers matching car (owned for 50 years this month as second owner), I retained the original block, heads, intake, exhaust manifolds, crank, and carb. FYI...I upgraded all engine internal components, balanced rotating assembly, much better cam, and had bowl work done on heads. I had fairly recently rebuilt the original AVS so I reinstalled it after the engine rebuild. It works great, except the primary shaft seems to have some resistance and does not want to return to the idle stop with the original return spring. I could turn it manually back to the idle stop. So I added a second spring, which worked for awhile. Now it's doing the same thing with 2 springs. Anyone heard of this? Suggested solutions?

Did you remove the primary throttle shaft when rebuilding? If so I don't think the throttle plates were reinstalled properly. The shaft could be twisted a little? I would remove the carb, turn it over and observe operation. That should give you the answer.
Mike

The choke fast idle cam could be the problem. If the engine is not fully warm it is working correctly.

I had the same problem with my AVS for my '68 Charger when I rebuilt it. I installed new shaft bushings. I ended up removing the throttle plates and installed the shaft without the plates. Determined that the shaft was bent just a few thousands. Once I determined where the bend was, I was able to tap the shaft with a brass punch while the shaft was in the bores and corrected the bend.

493 Mike said:

Did you remove the primary throttle shaft when rebuilding? If so I don't think the throttle plates were reinstalled properly. The shaft could be twisted a little? I would remove the carb, turn it over and observe operation. That should give you the answer.
Mike

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IHMO...
IF you removed the throttle plates, to rebush the throttle body or install new throttle shafts, it may be possible that they are not installed in the correct orientation. The leading and trailing edges are beveled and the mounting holes are slightly elliptical to allow the throttle plates to be "adjusted" (rotated ever so slightly) to ptovide a tight fit in the bore BEFORE tightening and staking the plate mounting screws. MAKE SURE THAT WHEN STAKING THE SCREWS TO SUPPORT THE SHAFT TO PREVENT BENDING. Just my opinion of course.
BOB RENTON