Idle not low enough and rough

first check for a vacuum leak and whether there is a solenoid that hits the carburetor that is for adjusting idle. to adjust carburetor lightly seat air screws then using a vacuum gauge back out for highest vacuum with gauge connected to a intake port or direct port on carburetor that is done after idle is down.I think what you are talking about going to air cleaner is the valve for hot/cold warm up. also check to see if choke linkage on opposite side of carburetor is applied as that will not allow a regular idle as well see pictures. also, check that the solenoid is actually working as it may not be and holding throttle open. then see pictures I think the second picture with arrow may be where your problem is so that lever should be loose if not loosen screw so it does or spray choke cleaner so it will work well.

So another thing I should mention is that the carburetor is brand new from guaranteedcarburetors.com. I bought it from them and they deliver it tuned and ready to bolt and go. The choke works perfectly, as it starts really high then warms up and goes down, but not to the 600 rpm range. Solenoid is old, as it did not come with the carburetor, but it does not appear to be holding the carburetor open. I will re-check that, but I am almost positive that is not the problem. Most likely a vacuum leak, or something with the vacuum system?

well a vacuum leak can do that as well what was previously mentioned. i am sending a picture of solenoid where arrow points if solenoid works this should be fro idle adjustment and other screw on carburetor should be for around 550 rpm. so when key is turned off solenoid stops and lets engine kind of choke itself out. See picture. if yours is not working then that is still the adjustment as it should allow throttle to come done unless the solenoid is frozen in place. if that is the case take it off and throw it away and use regular idle screw.

Ok, so it seems that the solenoid, wasn't doing much, so I took it off and capped the vacuum port. I have adjusted the air mixture screws so that now the vehicle idles smoothly. I started unscrewing the curb idle screw to bring the idle rpm down, but when I unscrew the curb idle screw, it just creates a space between the end of the screw and the piece of metal the curb idle screw is supposed to hit. So essentially, I can back out the curb idle screw more but it doesn't change anything because lever doesn't move forward at all. There is nothing blocking it from moving. I tried to push it forward, but it wont go. Is that supposed to be like that? Do I need to go back and adjust the mixture screws again to bring the idle down even though it's idleing smoothly?

I don't know if the lever has the capability to move forward because it doesn't go even when pushing it. Moves fine the other way to accelerate the engine, just doesn't go any further closed than where it is.

OK I finally made it here.

I reckon there's no need to paste in the message/ questions you sent me. Sorry I took so long, doing Honey-D0s most of the morning and early afternoon.

This thing still got the 'lectric choke?

Is the choke's butterfly standing fully vertical?

I was gonna tell you that messing with the idle screws is fruitless when the idle is like 800 RPM and above. You are then running on the mains and not the idle circuit so the screws sorta do nothing for the idle. Like mentioned up above there, many times it's a vacuum leak that throws the whole tuning deal out of whack. And continues to if you ain't capped or fixed all of 'em!

Which carb you got? The BBD with or without the stepper motor on the back?

How 'bout any other modifications?

Any bells and whistles that are not stock?

I already know your vacuum lines have been changed/ removed.

If you are not subject to emissions testing due to the age of your rig or just live in an area like me, it only takes two vacuum lines (PCV and Distributor vacuum advance) are need to run the engine, another one, if you have power brakes.

You are welcome to send pics of your engine from different angles (breather removed) and even some of the whole Jeep!

I've got more tuning for you, let's get the carb operating good 1st.

Try to answer the questions above.

The Medic

I have the bbd carb with the stepper motor on the back. I bought it newly rebuilt from guaranteed carburetors.com. No modifications to the engine that are present. Looks like some of vacuum tubes are not there, but i have capped off all the open ports. 2 caps on 2 ports that are black and stickig out of the manifold area, capped the port to my air filter intake hose, removed the solenoid from the carb as it appears rusted and broken. Also capped a vacuum port on the driver side bottom area of the carb closest to the wheel well and firewall. There were some other ports that were capped that sit on top of the valve cover. Will send pictures shortly. Also have power brakes.

See these images. Yes the choke butterfly stands completely vertical when fully warmed. Also have power brakes, aluminum valve cover and electric fan with aluminum radiator. Valve cover does not leak.

More pictures

More just in case

This has an Automatic choke. To set it I step on the gas which closes the choke plate. Not sure if it's electric, just automatic. Once warmed I step on the gas again to get it to a slower idle.

Idle should be 600 RPMs at 13 BTDC

actually seen as 13 BTDC at 600 RPM

This would be your final close the hood settings.

Did you get the idle screw to touch?

Are your steps still engaged (not floppy loose in front of their adjustment screw) allowing the actual idle screw to touch?

Do you know how to set your mixture screws correctly?

Have you checked your timing?

Do you have a dwell meter/ timing light/ vacuum gauge?

Old pic below of my neighbors neglected '83 carb (and Jeep)

The Medic

the idle screw is made to only go so far and idle was controlled by the solenoid like I originally said. it is /was for emissions so either get another solenoid or put the old one back on andsee if you can adjust eh screw in back from the original pics I sent you. showing which to adjust.

But the carb must idle back down!

So if you snatched out all of the adjustment screws

(and the non-existent now, solenoid, was still there)

The shaft would still have to rotate the throttle plates to the idle position.

Unless the steps were in the way of it's adjustment.

CJA31186 can you send us a closer-up of your steps?

How low can you get the RPMs at present?

The Medic

I have not checked my timing. I have a multimeter that measures dwell. I don't have a timing light or vacuum gauge, but can get them if I need them. I am pretty sure I know how to set the mixture screws correctly, but maybe I am wrong. You can see below what I did to set the mixture screws.

I look at the steps and they are not in the way of the adjustment. When the jeep is warmed up, the screw that was touching the ridged portion of the steps, now touches the top smooth area. I use my multimeter to measure the RPM's, and the best I can get it to run is with the rpms around 780-820 (the multimeter fluctuates a little bit, doesn't stay at exactly one rpm). That's with the low idle adjustment screw all the way out. You still see threads showing on the low idle screw, but if I take it out anymore the throttle will not go any further down, and just create a space in front of the low idle screw. Nothing is holding it back I just think the carburetor cannot go any lower in terms of the idle adjustment. If I turn the mixture screws any more clockwise to get the idle lower around 670-730 range, the engine will run rougher, and will stall out when I stop quickly when driving. So I have the mixture screws backed out about maybe a 1/4 to 1/2 a turn away from the spot where the engine will idle rougher and stall out when stopping. (the solenoid does nothing for the idle with or without it theres no difference.) At this point the only adjustment I can do for the curb idle screw is turn it clockwise to make the idle go higher, but can't go anymore counter clockwise because the piece that the accelerator cable is connected to seems to be at the lowest it can possibly go.

I will also upload a picture of the carburetor screws so you can see what I am talking about.

Here is a picture. Also, if there is a way I can get rid of the vacuum lines and emission crap to make the engine run better, I would not mind doing that either.

Also, forgot to add, how can I check to see if the timing is at 13 BTDC?

We'll get to the timing soon!

Let's see if this makes a difference, if indeed, the throttle linkage is holding the carb open.

From the idle speed screw, look at the throttle arm. There's a rod with a ball socket on each end. It connects the arm to the throttle bell crank.

Pop the rod off of the arm, Now the linkage has no bearing on the carb.

Can you get the idle down now?

Forcing it is not the answer (other stuff can be damaged)

Without seeing this situation, sometimes it's hard to explain.

In a correct situation, if there is a gap between the idle screw and it's stop/ anvil (whatever!) this would mean the throttle plates are COMPLETELY shut, it should not run at all.

It's hard to tell if they are completely shut on a mounted carb (things bent or internally binding might affect proper closing).

Turning the screw till it touches would sorta be zero, additional turning would begin to crack open the plates (which is, where it will begin to run)(or turning it a bit too far and backing it down to proper idle speed.

Gimme these answers so I can see if we are starting to get somewhere. Maybe we can get the demons out so you can continue!

I'll then send you a link that should help you get things checked out and get this tuned right.

Oh Yeah! Nice Lookin' Jeep!

The Medic

the pic and shows single arrow is for fast idle try adjusting the screw with double arrow outward and see if idle goes down

Ok, yes the screw with the double arrow is the screw I am talking about. So, today I tried disconnecting the throttle arm to see if the idle would go further down. It did not go any further down than where it currently is. If you see the picture in the last post with the double arrows, if I turn that screw any more out, the throttle linkage doesn't go any further. I think I have it set as low as it can go. When I take it further out the screw also gets a little wobbly. Should I try adjusting the air mixture screws again to bring the idle down to where it will almost stall then screw in the curb idle screw to bring it up a little? I mean I don't know if that will work either because the jeep seems to run a little rougher when using the air mixture screws to bring the idle down.

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

I just tried it with the arm that controls the linkage disconnected. Doesn't move any further. Look at the pictures of the throttle arm disconnected and screw turned out. There is also nothing blocking the arm from moving down.

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

Ok. And if it doesn't what would be the course of action? Also this carb has a lifetime warranty from guaranteed carburetors, so I can always send it back.

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

Please see image with notes. Are you sure it's not already at the lowest idle point, and maybe the air mixture screws are out of adjustment? Don't know what to make of it at this point.

It's also a brand new carb from the place I mentioned before. Bought it about 6 months ago.

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.

Perhaps this is due to the vacuum setup. I'm not sure if some of the hoses are even in the right place. The hose from the distributor is connected to a t shaped plastic piece. The two locations on the carb that some say the hose from the distributor should connect into are not connected to the distributor hose. Ideally I'd like to get rid of these hoses and keep only what is necessary to run the engine smoothly.

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

Ok great. Thanks for the information. The link shows me how to reroute the vacuum system with the existing carburetor right?

So whether I switch to a 79' bbd with no stepper, or eliminate the computer and stepper on mine, I would be left with the same result right? Either way, would I have to adjust the timing after whatever option I choose? Also, have you heard of the nutter bypass? It's a way to get rid of the stepper motor and rewire the carb and engine to run without the computer and stepper motor while keeping the same carburetor. Not sure if the nutter bypass would be better than getting the 79' bbd.

If I go the 79' bbd route, how do I get rid of the computer and other unnecessary parts to get the engine to run right?

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

I am understanding the things you are telling me. So basically, I'm thinking of just buying the 79 BBD that you sent the link for. Just to make sure I got this right: Once the carb is installed, we route the vacuum lines per your recommendations on the previous post. Once the vacuum lines are rerouted, we tune the engine and take care of the timing is that right?

Only thing is, once I get the 79' BBD what do I do with all that wiring for the stepper motor and the computer that we no longer need? Also, the 79' BBD has an automatic choke right? I don't want to install a manual choke.

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

Ok so I ordered the 79 bbd. Will be here Friday. Next step would be to install and follow vacuum line routing from your diagrams in the other post you sent me the link to, right?

Nice jeep pics. Are they all yours?

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

Ok, so the pvc breather connects to the carburetor with a connection piece on it that has wires going into it. The brake booster connects into something below the carb and above the EGR. See pics.