Carter AVS Rebuild Jet/pump/screw/gasket? Removal/Replacement

[HS 69 Charger]

2 new questions before assembly.

1 The rebuild kit has two new float seats and needle valves. What I had not noticed is the "original" ones are not matched. I see no notation that they are different and don't know why unless they are simply different vintage. See pic below. I planned to install new ones that are matched but wanting to make sure why the one is longer plus has side "vent/flow" holes.

2. on the under side of the air horn in front of the Accelerator Pump jet area is a hole with a collar, retainer, spring, and ball. In the service manual on a top view this is labeled as Off Idle Adjustment screw (not adjustable) and is sealed. I did not remove this but cleaned in place and with compressed air I verified if blown from the outside (top side vent hole) it pushes the ball and spring down. I got out all the moisture from cleaning. Is there anything more needed?

 

[RJRENTON]

2 new questions before assembly.

1 The rebuild kit has two new float seats and needle valves. What I had not noticed is the "original" ones are not matched. I see no notation that they are different and don't know why unless they are simply different vintage. See pic below. I planned to install new ones that are matched but wanting to make sure why the one is longer plus has side "vent/flow" holes.
View attachment 1843164
2. on the under side of the air horn in front of the Accelerator Pump jet area is a hole with a collar, retainer, spring, and ball. In the service manual on a top view this is labeled as Off Idle Adjustment screw (not adjustable) and is sealed. I did not remove this but cleaned in place and with compressed air I verified if blown from the outside (top side vent hole) it pushes the ball and spring down. I got out all the moisture from cleaning. Is there anything more needed?
View attachment 1843162

Regarding your #2 pix, yes...it is the off idle air adjustment...it works via differential pressure to help with emissions and as a pullover air bleed during deceleration from a high speed coast down....emissions again.....factory set for proper operation...no need to adjust...keep it clean as you've done.
Which needle seat to use ......match the one in the carb.....making sure, after the new needle/seat combination is installed, to get the correct float setting, especially the float drop is correct with the float pull clips installed....double check float settings.....to be sure.....just my opinion of course.......
BOB RENTON

 

[Geoff 2]

The 'windowed' n/seat flows more for the same orifice size. The important measurement is the seat/hole size that the fuel comes through. There were about 4 sizes & the size changes the float setting slightly. Bigger hole, increase the float level dimension slightly.
The original n/s for the #4638 is the 25-860 which have a 0.101" orifice.

 

[66fs]

The red arrow needle and seat are probably original. Just use the new ones and set your float and drop dimensions and you should be good. I do not know if the originals are available.

 

[HS 69 Charger]

Thanks to all the replies. The Rebuild kit contains two Needle/Seats part 31-512. Documentation shows this orifice at .110 I checked them all and the Long vented one (expected to be original) is indeed .101 orifice size. All the rest check out as .110 I believe the long vented one was in the position on the Fuel Line Inlet side. That long step protrudes about half way into the fuel inlet "bore" that runs across the carb.
I will plan to use the new ones and set them as defined in the kit. Which is 5/16" Float Level and 13/16" Float drop. Both are marked with * which match the diagram showing these are distances from gasket face to top of float at end.

 

[HS 69 Charger]

Next up is the Vacuum Choke assy. When I got to the adjustment, I couldn't seem to get the Choke to move using an external vacuum. I was simply using a hand pump with a tee to the Vacuum Choke and Vacuum gauge. I saw mention that some units have a bleed off so this test might not work???
Can someone confirm if these can be tested and how.
I'm almost done with all my adjustments and this can be done on the vehicle so I might get it all back installed and see if the constant engine vacuum creates any movement.
Doesn't appear these are available to replace but Mike's Carburetor appears to rebuild them? Any other advice on this.
So close till I stumbled on this.

Thanks,
Martin

 

[AR67GTX]

A vacuum gun should work fine to activate the choke pull off. They don’t have any internal bleed off as far as I know.

 

[Geoff 2]

You should use the same size n/s that was original on both sides. As I said earlier, changing n/s size AND fuel pressure changes the float level. I have no idea why some n/s assemblies have the extension, might have been a 'good idea' at the time but was found to....do nothing...& dropped.

 

[HS 69 Charger]

Thanks @Geoff 2 . It appears the Rebuild kits have standardized to the .110 size so since that is the new ones I have, that's what I'm stuck with. But your graphic tells me to add about 1/32" to the Float height. The graphic is really great to adjust as the parts you get seem to have shifted a bit over time. Since I am "small time" with only 1 carburetor, I really can't go to my draw and grab parts from another unit or my NOS stash. So I'm a bit at the will of where the replacment part market takes me. But your data/info helps me keep it on track. Thanks so much for sharing.

Now, I'm off sourcing a vacuum choke pull off. Found a few. Either very old NOS Mopar stock or new but 3rd part replacement. Even that is hard to find as even the 3rd party's appear to be obsolete (like Walker 101-541).

 

[66fs]

AVS pull off

https://quadrajetparts.com/pull-fits-3832-p-776.html

Choke Pull Off Vacuum Break Carter AVS 4B 1968 - 1971 MOPAR 2933196 202-404 | eBay

Finish varies. If your car is hard to start or you suspect a vacuum leak, try replacing your choke pull off; it may just fix your problem!

www.ebay.com

 

[HS 69 Charger]

Many thanks. That's exactly the one I found as available as a 3rd party replacement. Really appreciate the confirmation.

Martin