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Outer barrel (ie passenger side) does 1-2-7-8, inner does 3-4-5-6.

Well I had the packard hooked up to more machines today than ever. It was like a patient in the hospital. Tach, Timing light, oscilloscope and CO analyzer.
With all these fancy tools that we have in our classic car club here, the biggest difference I made was advancing the ignition a little bit. I went from 5 or 6 degrees to 8 degrees. That, and the choke tube going to the intake manifold had a giant leak. I was wondering where this sucking sound was coming from at the back of the engine.
How does the tube that goes from the ex manifold to the choke work? Won't that always create a vacuume leak? I temporarily plugged it with a ball bearing, but having a choke warmer will be nice one day, but not really needed.
Does that tube pull manifold vacuum, or from someplace above the throttle plates in the carb?

With some more advanced timing, and some more fiddling with the idle mixture screws, I think I have a better idle, and hopefully better fuel mileage.
Here is a picture from the scope, I think I would need a teacher to help me really get much helpfull information out of the scope. At least all cyls seem pretty even.

Now coming up to a light when I go out of gear, the idle doesn't dip low and recover. It seems more stable.

Oh, and my idle mixture according to the CO reader is 0.45% which makes an AirFuelRatio of 14.3:1 which is pretty darn close to stoich!

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I'm still a little confused about the choke tube. There is a piston that is exposed to manifold vacuum, which pulls the choke plate open. The bithermal spring pulls the choke plate closed when cold and relaxes as it warms up. The choke tube pulls heated fresh air from the exhaust manifold.
When the engine is warmed up, and the choke is fully open, should the piston be down, and then that stops the airflow through the choke to the intake plenum? Or does the choke mechanism always bleed some air into the intake?
Does the end of the choke tube that is buried in the exhaust manifold have a certain size orifice to limit the air bled through the choke tube?
My choke tube was broken off at the ex manifold, so I had jammed the new tube in, but it opened up. Is it recommended to JB weld the choke tube back to the intake manifold so there are no more external leaks?
Thanks all, still learning!

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The air going thru the choke portion of carb is fresh air, not manifold gasses. As I understand it the choke stove is probably a stainless steel tube or something not prone to rust and damage from hot exhaust and is a press fit in the manifold. It has a bottom end open to the outside air. Not sure there is an actual orifice in the bottom but maybe a pinch so the partial closure will restrict the air somewhat. I think the purpose of any restriction is more to slow the air down to give it a chance to warm.

The tube connected to the carb is a snug fit into the exposed upper end of the choke stove. It is not an airtight connection but being a close fit vacuum will pull the air thru the stove rather than admit a lot of cold air around the tube edges.

Perhaps someone with a manifold laying around could examine the bottom side of the manifold for the tube opening size or even take a photo.

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There is always airflow through the choke, but the quantity is negligible as far as affecting the mixture. There certainly should not be enough airflow that you can hear it. If you are hearing a vacuum leak at the carb, it is probably coming from the starter switching mechanism. You will find that the actuating cam is in upside down. Remove the switch head, pull out the contactor and cam. Turn the cam so that the notch faces up and reinstall.

Thanks guys, my carb was rebuilt by daytona carbs in florida 5 years ago, so I figured the choke and starter switch were correct, but I will check after your suggestions. I think the choke stove design changed over the years also, but design principle should remain the same.

I think the choke stove design changed over the years also, but design principle should remain the same.

Yes, essentially the same on the V8 Packards, a small diameter pipe which passes thru the exhaust manifold, swaged at both ends for closure to the exhaust gases so it's in effect just a heated passage way thru the manifold.

Mike, I know this is for for 21st and 22nd series but goto to this linkhttps://www.packardinfo.com/xoops/html/downloads/49_CarburetorTrainingBook.pdf
and on pages 18 and 19 is a very good description of how the automatic choke works. I would suggest to read the whole Manual it has very good details on how a carburetor works.
Wes

No carburetor work done in the last days, but I did get my metal valve stems installed and the wheels and hubcaps are back on the car. Looking a little more classy with hubcaps all around.
Wes, thanks for the link to the carb training manual. It is always good to read that stuff. My last deep dive into carb work was on the Solex carbs in my Porsche, and they are rather different. No metering rods, and no choke with the solex carbs. I'll get back to the choke stove and starter switch check next.
I think I will also install a vacuum gauge in the car. My plan is to tap into the line going from the intake manifold to the fuel pump. I have to see if this is an appropriate place to mount the vacuum gauge.

The Euro meet is getting close! We plan on driving the circa 250 miles over two days. That will be easier on man and machine than going in one day. We plan on about 150 miles the first day, and 100 miles the second day.
I've only accumulated 300 miles on the car so far, but we are going to go for it! (I still need to do some more finishing touches)
I am already planning on what spare parts, supplies and tools I will pack for the trip, and I have ADAC, which is like the German AAA.
After reading the Carb training manual that JW posted, I will try and richen up the idle mixture to about 13:1 Air fuel ratio and see if I can get the idle vacume greater. I am installing an aux triple gauge cluster on the lower side of the dash with battery voltage, oil pressure, and manifold vacume.
As I remember, there is an oil galley tap on the right rear side of the engine, has anybody used this for an oil pressure gauge? This location is more hidden than the original dummy light pressure tap. I don't really want to plumb in the oil pressure line there. I will be keeping the dummy light function.
I had been running 35 psi (max psi) for my American Classic tires, and just went down to 33 psi. The owners manual says 24 psi... I will experiment a little with lower tire pressure. I guess somewhere between 25 and 30 psi will be the sweet spot. Any suggestions?