73 Carter Thermoquad mixture setting - Alternate Procedure

[WH23G3G]

Ok I've been away from working on my Charger for quite a few months now. I've been working to get my 65 Valiant up and running before it gets too cold here because it's outside right under at least 100 yr old oak tree. So with just a few more things to do on it and then I can move hopefully to a safer spot. So my Charger has been sitting in another garage. It's basically done enough to be shipped to the shop to be checked over, but I wanted to give it one more crack at the carburetor adjustment just to see what happens. I'm one of those that has to have a step by step procedure to follow. So since I don't have the expensive gas analyzer I want to try and adjust the mixture by the Alternate Procedure listed on the emissions label under the hood which is correct for my 73. It seems pretty simple to follow. It says to Adjust idle speed screw and mixture to lean best idle at 850 RPM. Then the next step says without touching the speed screw turn mixture screws clockwise (lean) equally to reduce speed to 800 RPM. Does that mean you are doing the adjust at least twice? Once to get it at 850RPM and then another to 800 RPM. After several failed attempts to get help from some mobile mechanics I see everyday I've got to try it again by myself. I want it to at least run when I take it to the shop, I'd love to be able to drive it to the shop so I can just get it up on the lift and check everything out I did with a mechanic. 

[Chryco Psycho]

adjusting that way would meet emissions , but it will not run the best like that , you want to adjust it so it idles at its best so turn the screws out until rpm does not rise any more & or highest vacuum & turn it in just until it start to affect idle quality / vacuum

[WH23G3G]

I guess I can try with the vacuum gauge I have. I know I've read you're to adjust it so it has the highest vacuum. I know what kind of cam and accessories affect the amount of vacuum an engine should put out. This is the specs on the cam I put in when rebuilding the engine. Sealed Power kit KC-661 .449 .464 LIFT, 214/225 DURATION at .050, 292/309 DURATION at .006, 115 Lobe, 46 C/L. I had the machine shop install the cam and cam bearings. I also have factory power brakes and a/c but I'm not charging the a/c until I get some miles on the engine. So knowing this, is there an acceptable vacuum number I'm looking for so I know I'm getting close to the highest vacuum setting. I think 22 inches is ideal? When adjusting do I adjust one screw to get high vacuum and then move to the next screw to get highest vacuum or do I do little on one and then a little on the other screw? Oh yeah and where do I hook up the vacuum hose to on the carb or on the manifold nipple? 

[flyinlow]

Manifold vacuum port on the carb,such as the one that powers the factory air cleaner, should give you a good smooth vacuum sorce. 22" of vacuum at idle would be hard to get even with a stock stationwagon cam. My mild build 446/lunati 60303/ 24* BTC/ Themoquad idles about 14" in park warmed up at 950rpm.
Adjust idle mixture for best rpm/vac, then lean slighty untill the idle suffures. I have a AF ratio guage , its about 13.0 :1 at idle,leans out above idle. 

[WH23G3G]

Ok I did the standard what everyone says and all the tech manuals. I turned the screws all the way in, backed it out 1.5 turns exactly. It ran low idle, so low that I couldn't get to the idle screw quick enough before it died. Plus it was making you tear up right away rather than doing it after running a few minutes. So I did like the factory Chrsyler service guide said and ran the idle stop screw in and backed it off 1.5 turns. I'm using that to get the idle up since this carb doesn't have the idle solenoid. I've got the original 6321S with original solenoid that I havent put on yet because I know this carb can be tuned to run good. So I talked to a mechanic and he told me to back out the mixture screws another .5 to .75 of a turn. I came back home and backed it out exactly .5 more turn started it up and it idled about 700-725 and it actually sounded like a pretty healthly idle and was staying running. I think I've got it well enough to get out or I'm getting close. The spec sheet in the Chrysler book says 750RPM for the 6321S carb. There also wasn't a sign of gas fumes either when I retweaked the screws another .5 a turn a sign that hopefully I am indeed getting it closer to being "right". I also bought an economy vacuum gauge to later install. I'll hook it up and see where I can get the vacuum to. The best part was I don't think I noticed anymore oil leakage from the valve covers and not as much smoke from the manifolds. It sounded to me like it was running pretty good.

[flyinlow]

Glad it is running better. I usually back the screws out 2-2.5 turns for starters. Dont over tighten them! Just snug. Then tune for best idle/rpm /vacuum. Then lean slightly,let your conscience be your guide. What the factory sticker said for a new engine to meet emission standards and what works the best on a 40 year old engine is probable a little richer. One thing I check is that if you turn both screws in far enough (lean) the engine dies, This means the throttle plates are about the right amount of open for the idle circuit to work right. Sounds like you already passed that test. Idle rpm is kind of a guide line. What works well for you.

[WH23G3G]

Yeah I'm a little more excited about finishing the adjustment procedure now. Because although it's not 100% perfect I think it might actually be good enough to get it down the street and back. I'm hoping to have a helper this weekend if it's nice so that I can move the car out of my garage and gather up the pictures of each side of my car. That way I can mail in the pictures to get insurance and then get a tag. I do have a couple of small issues I would want to address before I take it out. I noticed the turn signal works only on one side now and it's slow. I'm sure it's a ground issue. The tag light doesn't come on but you mess with the socket in the back and it comes on. Another ground issue I'm sure. But everything else seems to work. But I'll start it up and move it out and see how it acts this weekend.

[WH23G3G]

The idle and mixture seem to be ok still when we were messing with it today. But we were trying to make sure the fast idle is working. Because that was part of the initial problem when starting it up it would die unless you hold it down for awhile. But the choke is working. It's the factory electric choke. When I started it up first thing today it didn't stall at all it was nice and healthy sitting at about 725-750 RPM. But I don't hear the fast idle working when I start it up. The factory fast idle is 1800 RPM after 500 miles. I closed the choke by hand and tried to adjust the long fast idle screw but of course as soon as I closed the choke the motor died. So how do you do that? I turned in the long idle screw with the choke closed and the screw on the highest step of the cam and turned it in until it just touched. I restarted it and it was up there about 1200 RPM, but when I zapped the gas pedal it didn't drop back down, it was still at the same RPM. All those linkages are complicated on this Thermoquad. I don't even understand how you adjust the fast idle if you have to have the choke closed it will die.

[flyinlow]

Thermoquads have a lot of bending linkages to adjust and interrelated adjustments . The good news is most of them are already made at the factory and just need to be checked after an overhaul. The fast idle is the same as many carbs.
Fast idle adjustment: Warm up your well tuned engine. Turn it off. Push the throttle open slightly. Close the choke . Release the the throttle. Let go off the choke. The fast idle screw should be on the top step of the fast idle cam. Without touching the throttle,start the car. Adjust the rpms to the disired number with a warmed up engine.
Now when you start your cold engine it will not idle at 1800 rpm if that's what you set,it will idle about 1000 rpm at first then as the engine warms it would speed up to 1800 rpm if you did not move the throttle. Most people "kick it down" or just start driving and the carb comes of fast idle as it warms up.
By the way, you have an electric assist choke. It still uses exhaust heat routed through the bottom of the intake manifold by the heat cross over  valve to warm the choke coil. The electric heater just helps it to make sure the choke opens quickly. Assumming it is still original.