Idle not low enough and rough

You might need to disconnect throttle linkage then adjust carb for the idle then reconnect/adjust linkage so it will work.

Take the carb off and see if the screw gets any closer to where it is supposed to meet if it does then there is either a gasket or intake problem that the butterflies are hanging up on

I dont' know what to tell you as I can't see it to make my own determination. I would guess get another carb.

OK,

I'm going with the metering rods maybe being adjusted incorrectly or been held upside down while the throttle was actuated.

Before we "Dig In"

Snatch the clip off of this linkage, pull the linkage out of the arm.

See if the screw will 'back out' and the shaft rotates more closed

I made a special pic for you below.

We might also use this old carb to show how to adjust what's under the cover if we need to.

The Medic

Idle screws only smooth the idle out and not determine the rpm of idle. As yousay it runs rough you should at least try what I suggested as the plates may be to big not allowing it to close as it should. This carb wasn't only used on jeeps it was very popular with most Chrysler products as well. Beside you migh tfind that the reason of the rough idle is due to a vacuum leak. With all I've gone through on this I really suggest you take it to a mechanic who can actually see what is going on. As it seems no help at all on here.

Here are two pics one other thing and this is the last i'll answer is to pinch off vacuum line to canister purge see if itchanges if it does the solenoid there is shot as it should n't work at idle. Two pics for system.

I don't know what you spent on your carb.

I asked you earlier a few questions, you kinda responded back with eliminating stuff is no problem.

Your rig is over 30 years old (mine are older). Things just don't work as they used to, if they work at all!

The Carb/ engine set up you have was used from '83-'86 on CJs.

In my opinion, the better CJs were made from '79-'81. They finally got everything right and Everything was really simple (or EZily made simpler).

My present daily driver is a '77 CJ-5, I have pretty much upgraded it to like a '79 (and made even other modifications without straying too far from a basic stock Jeep.

The '79 carb has no stepper/ no primitive computer control (which won't work correctly if all of the input stuff ain't connected/ working, thus rendering it's purpose useless and even what's left as "Default" lacks in proper operation.

Most folks that come to me with terrible running Jeep are sorta roped into doing most of the (EZ) work, and tuning with me explaining/ showing/ using my tools to get theirs all fixed up. I kinda do this to them so they can maybe diagnose and repair their on problems in the future. 99% of them are very grateful and I come out good myself!

Most of the time this may take a couple or three visits, most leave with a new carb (THEY INSTALLED), a lot less vacuum lines, all new tune-up parts, Maintenance on stuff neglected forever and confidence that the job was done well, the ability to diagnose and even make simple repairs. Usually they obtain a manual and learn how to use it!

I'm not selling parts, they go obtain them. I sorta learned this form of repairing and camaraderie down at the Automotive Rec Service Center where I worked on my 1st two Jeeps during my limited spare time as a U.S. Army Airborne Ranger.

Do what you gotta do, but a '79 BBD will run your Jeep just fine and it has no stepper. This link below is a NEW (not rebuilt w/ worn parts) Carb. These are found here and there on the site, Of the dozen or so that were ordered in the past couple of years have been identical. Other than tightening some of the body screws to my liking, I have had no problems with 'em even though they are copy cats.

The price is right and this one has free shipping. What a Deal!

http://www.ebay.com/itm/New-2-Barrel-Jeep-Carburetor-BBD-6-CYL-4-2L-258CU-Engine-AMC-Carb-Carter-Type-US-/182061362581?hash=item2a63b3ed95:g:YQ8AAOSwMORW7xZa&vxp=mtr

Now, if you wanna play with yours some more.

The Mix screws are not for IDLE speed per say, They get the air/ fuel mix right. The idle screw is for idle speed. Getting mad and forcing them in, kinda ruins the carb!

This was from a good while back.

It may could be re-written better.

I'm aiding a feller with a 304, I'm using my 258 as a demonstrator. Cool thing here is that all you have to do is rule out the 304 portions! Pretty much an old school 1 cylinder- a 12 cylinder sorta tunes the same. Here's the link.

https://www.2carpros.com/questions/jeep-cj7-1985-jeep-cj7-stalls-when-hot

Return with news!

The Medic

The computer is tied into ignition stuff (not the carb).

We'll just continue to call a "79's systems "The Standard"! (TS)

TS's and nearby models ran 4 wires from the ignition module, 3 went to the distributor, one dropped off to the coil.

Later stuff ran some of these wires into the fire wall to the computer, then they popped back out mostly to the distributor.

Pretty much, the Nutter whacks 'em loose on the Newer CJs, and puts 'em back like the ole "TS" system.

Days ago another CJ came on board with a problem, it shifted more towards the Nutter issue.

It seems that we all get to jumping around all over the place and don't finish the issue at hand!

Here's a link to that one, READ IT, DON'T get all involved till we get the carb issue better! I think It was hard for this guy to understand my southern hillbilly kinda lingo.

https://www.2carpros.com/questions/ignition-issue-3069929

I only make suggestions!

Return stepper carb for refund, probably more than enough to obtain an Ebay special (and spares!)?

Way back, I told you we could run on just a few vacuum lines, we can do this.

Did you soak in any of the Tune up on the 304?

Are you understanding the stuff I'm shoveling?

The Medic

If I were there, I might help you clip away the unnecessary wires, sorta cap off anything live. Sometimes my victims get 'skeered'! With all of the drastic changes going on under their hood. So we simply bundle up the excess wires and tape/ zip tie 'em out of the way. This seems to soothe them thinking that 'it could be re-installed' if the planets in the solar system didn't line up. We'll stick with that plan!

So,

With all of that said, in the end you will have 3 necessary vacuum lines (as far as vacuum lines go, only 3 that could leak, only 3 to ever replace)

We will cap off unused vacuum ports on the carb and any on the manifold that are not needed (Some folks like to cap the dead stuff too)

A basic BBD, lesser expensive, with no extra bells and whistles (that probably did not work anymore)

We'll Nutter your ignition wiring

Beings that all of the over-engineered stuff is gone or dismantled,

Your Jeep now will have the characteristics of a '79, We will tune it using '79 specs!

How's all of this sound?

Send me a pic of your ignition module to include it's own wires and connectors. No need to un-install it.

The Medic

Send a good pic of the fender side of your intake manifold (need to see the middle well)

Show me where the brake booster gets it's vacuum.

Show me where PCV is getting it's vacuum.

MY JEEPS! '77 and '46 are both legal drivers, my buddy and I have sorta personal Willys salvage yard in the field behind his house.

I'll draw you up a vacuum diagram.

Vacuum caps:

1" long fuel line, whatever size needed (better than vac line) with short bolts for the actual cap stuffed in one end.

OR

Vinyl (usually colored caps) I think harbor Freight had 'em cheap.

Refrain from Rubber Vacuum Caps- They seem to rot pretty fast and you'll have a vacuum leak on an unused port (you will probably overlook it for a while). This will affect your performance, you will not catch it right off, pretty much you will not be a happy camper!

We will still need to address the IGN module stuff too.

Send a Pic of your "full" IGN module, wanna see the wires and connectors in the shot (you can leave it hooked up)

The Medic