Hot engine won't idle smooth

[caveman]

I believe you're right about the carb Wooly and all of the adapters for that carb that I've seen have recessed Allen head bolts to hold them down. I am interested in what ever the manifold is though. It looks like a newer fuel injected manifold to me.

 

[Hedgehog]

Well, it appears that we are going to have to wait. He's decided to change the fuel filter and aint' nothin' going to happen until he does. Even though it would only take about 5 minutes to check most common problems with vacuum leaks, then there's the elephant in the room, which is the un attached vacuum advanced hose. Again a 5 minute job. But, it isn't an electronic fuel injected engine, so the prospect of working on a carb. is daunting. .... Apparently anyways.

 

[dtrojcak]

Well, it appears that we are going to have to wait. He's decided to change the fuel filter and aint' nothin' going to happen until he does. Even though it would only take about 5 minutes to check most common problems with vacuum leaks, then there's the elephant in the room, which is the un attached vacuum advanced hose. Again a 5 minute job. But, it isn't an electronic fuel injected engine, so the prospect of working on a carb. is daunting. .... Apparently anyways.

I'm not sure why you feel the need to be condescending, but if you don't want to help, don't reply.

The jeep is a 2nd spare vehicle, and not a daily driver, so it is not a priority project for me. I apologize if my time table does not line up with your life.
I work till 7pm 4 days a week and have other priorities once I do get home. The repair of the jeep is near the bottom of the list.
I did not realize It was requirement to post to immediately implement any advice I was given. I apologize if I missed that in the forum rules.

The unattached vacuum hose didn't concern me because it was like that a year ago when I bought the jeep, and this problem only started a few weeks ago. In addition, the hose is all cracked up and would need to be replaced, so it's not exactly a 5 minute fix.

I never said working on a carb was daunting.
I simply said this was the first non-cpu vehicle I've worked on.
They're obviously different, but I've worked on carbs on lawnmowers, generators, weed eaters, and outboard engines, just never a vehicle.

There's no need for the condescending remarks attempting to classify me as a moron trying to fix an engine.

 

[Hedgehog]

Simply stating the facts as they seem to me. You may be correct in that your problem is in the filter. But you definitely have a problem with not having your vacuum advance attached and you definitely have a big vacuum leak if the port for the advance isn't at the very least plugged. So it is possible that you've been running lean for a very long time. It still needs to be attached, even if it is plugged you need that advance to be working. That is unless there is some sort of computer hooked up and running things. If not, this is something that needs to be addressed. The same can be said for the possibility that you are somehow missing the studs/bolts that are supposed to be holding down your carb. None of this actually takes much time at all to check out or do. And I am trying to help! Probably 90% of the responders here believe that your jeep is having vacuum leak problems and that is why it is running lean and can't keep running at idle once hot and the choke (an enriching system) is off. An older jeep is a simple thing really, feed it and it will run. One more thing to consider, a vehicle running lean can do serious damage to the engine if left for long enough. Seriously, even if you find crud in the filter is causing your current problems, the other issues need to be addressed and soon.

Okay, these things may not be a 5 minute fix, they are a 5 minute diagnosis. Then while running around doing other things you will need to stop at a auto parts store. With parts in hand it is a 5 minute fix.

Also, I don't really care how long it takes you to get to the job, we all or at least I work for a living too. In my previous post I was wondering if we'd lost you due to board troubles. Glad your still around. I am in hopes that the CJ's problems are small ones and are easily taken care of.

 

[dtrojcak]

Also, I don't really care how long it takes you to get to the job, we all or at least I work for a living too. In my previous post I was wondering if we'd lost you due to board troubles. Glad your still around. I am in hopes that the CJ's problems are small ones and are easily taken care of.

I apologize for lashing out earlier.
It's been a frustrating morning at work and I was checking for new replies during lunch and it seemed like you were annoyed because I hadn't posted in 16 hours, 8 of which I spent sleeping.
Then the condescending remarks about the carbed engine being daunting for me just pushed my buttons.

I appreciate all the positive responses do far and I will try the advice given as soon as I have time. I will report back my results either way.

 

[Woolyworm]

[emoji106]


Wooly

 

[Hedgehog]

In attempting to be direct I can come off as being snarky. The carb. comment was an attempt at being ironic. I am totally lost when it comes to automotive electronics, EFI engines, while they are far more efficient are completely daunting to me. The old saying, "I looked under the hood, and under the hood looked back at me and I called the mechanic.", most certainly applies to me. I can't help but smile what younger folks say they are lost when it comes to working on a carb. , but have no problem with an EFI engine. Lost I'm tellin' yeah, I'm lost......

 

[dtrojcak]

In attempting to be direct I can come off as being snarky. The carb. comment was an attempt at being ironic. I am totally lost when it comes to automotive electronics, EFI engines, while they are far more efficient are completely daunting to me. The old saying, "I looked under the hood, and under the hood looked back at me and I called the mechanic.", most certainly applies to me. I can't help but smile what younger folks say they are lost when it comes to working on a carb. , but have no problem with an EFI engine. Lost I'm tellin' yeah, I'm lost......

At 42 years, it's not often I get called young.
Thanks for that.

One of the reasons I bought this jeep was because of the lack of a computer.
I am not scared of wrenching on anything on a vehicle, I just lack the knowledge on this one.
My daily driver is a '02 F250 7.3l PowerStroke. I've completed several repairs on it with the help of others on forums like this. The advantage for this engine is a code scanner will allow the computer to tell you what is wrong most of the time.
I don't have this luxury on the jeep and I don't have the experience yet.
I'm at a little disadvantage because I may not know something is wrong because it was like that when I bought it, like the carb bolts that were mentioned, so I have to rely on others for advice.

It's all good.
The typed word often doesn't come across as intended, especially if the reader is already frustrated as I was when I read this earlier.
Again I apologize and am appreciative of all help.

 

[Woolyworm]

Alright, now that we know each other.....are there bolts in that thing or not?! [emoji1]


Wooly

 

[Lumpy Grits]

At 42 years, it's not often I get called young.
Thanks for that.

I have 'kids' your age
I turn'd 64 in March
LG

 

[dtrojcak]

OK, a brief update and answers to some of the questions asked.

The intake manifold has Offenhauser stamped on it. It was on the jeep when I bought it.

The only holes I see under the carb, don't go to anything.
Which holes are ya'll referring to?

I do not see where the distributor vacuum is supposed to be connected to the carb. As far as I can tell, there are no open ports. All ports are plugged as far as I can tell.

It seems that the rough idle was due to a clogged fuel filter.
I replaced the filter this morning, then took a short drive down the highway and back. The engine idled smoothly when I arrived back home.

I was mistaken in thinking I had already replaced the filter. When I went to retrieve the old filter, I realized it was actually the new filter I had purchased. Apparently, I took the new filter out of the box, and that was as far as I got, lol.

I guess my next step will be to get a service manual and investigate where the distributor vacuum hose is supposed to connect, and where the other vacuum leaks ya'll mentioned are coming from.

Thanks again for everyone's help/advice.

 

[Hedgehog]

Thanks for the update.

"The only holes I see under the carb, don't go to anything.
Which holes are ya'll referring to?"

Look at your Carb. There should be 4 tabs on the bottom where it is attached to the manifold. In one of your pictures there appears to be two tabs with no bolts or studs holding the carb to the manifold. It could be an oddity of the picture, make sure there are bolts or studs holding ALL the tabs down.

Distributors like what is referred to ad delayed vacuum. Basically the vacuum is held back until the engine is hot. But many older vehicles ran on simple vacuum. If I were you I'd lay the hose out and see where it WANTS to go. Old hoses take a set and will show you where they once were. If that doesn't work pull one of he plugs off and see if there is vacuum at the port. If there is, feel free to plug in the hose. If it were me I'd first check the timing with a timing light, then plug in the hose and see if the vacuum advance is working by using the timing light again to see the difference in your timing mark. A properly operating vacuum advance will increase your engines power and ensure it's running properly.

Check for cracked plugs. I mentioned this before, I used nice new vacuum port plugs on my CJ. Within a very few months I found some of them cracked. So, check all your plugs closely. Replace the broken plugs with new ones making sure they are the proper size. Don' force a small plug on. A new one should be tight but not forced in place.

 

[dtrojcak]

Thanks for the update.

"The only holes I see under the carb, don't go to anything.
Which holes are ya'll referring to?"

Look at your Carb. There should be 4 tabs on the bottom where it is attached to the manifold. In one of your pictures there appears to be two tabs with no bolts or studs holding the carb to the manifold. It could be an oddity of the picture, make sure there are bolts or studs holding ALL the tabs down.

Distributors like what is referred to ad delayed vacuum. Basically the vacuum is held back until the engine is hot. But many older vehicles ran on simple vacuum. If I were you I'd lay the hose out and see where it WANTS to go. Old hoses take a set and will show you where they once were. If that doesn't work pull one of he plugs off and see if there is vacuum at the port. If there is, feel free to plug in the hose. If it were me I'd first check the timing with a timing light, then plug in the hose and see if the vacuum advance is working by using the timing light again to see the difference in your timing mark. A properly operating vacuum advance will increase your engines power and ensure it's running properly.

Check for cracked plugs. I mentioned this before, I used nice new vacuum port plugs on my CJ. Within a very few months I found some of them cracked. So, check all your plugs closely. Replace the broken plugs with new ones making sure they are the proper size. Don' force a small plug on. A new one should be tight but not forced in place.

I'll take a look at the carb bolts and take some pics when it quits raining.

The hose attached to the distributor is very flexible and simply hits the axle.
Should I be looking for something on the carb or on the engine?
The hose isn't long enough to reach the carb.
After the rain stops, I'll try and see if I can find anything that the hose could plug into.
If I find something and put my finger over the hole, should I be able to feel the vacuum?

 

[Hedgehog]

It should attach to the carb, occasionally the manifold. There should be only one hose coming off or too the distributor. Even that technically doesn't attach directly to the distributor. Do a google search for vacuum advance, there should be a ton of images and more than likely "how too's" on how it works. You don't have to look for jeep specific articles either, most distributors are pretty much the same in the way the advance works.

I just did a google search on "Vacuum advance", as expected there is a bunch of information out there on the subject. I just read an article and learned a little more than I knew before about vacuum advance. When I get the CJ back on the road I'll be putting some of what I learned to use.

 

[Lumpy Grits]

Always carry at least 2 spare fuel filters with you just in case. Sooner or later you WILL need'em.
In about a week or so-I would change that f'filter again.
Does sound like you need to remove the gas tank and flush it.
You can get your FSM from here-
Jeep Service Manuals ? CBJeep

LG

 

[dtrojcak]

Sorry for the delay in updating, I've been busy with life, lol.

I finally found a picture of the carb that showed where exactly the vacuum advance port was located.
It's on the backside of the carb, partially hidden by the electric choke.
It was unplugged, so it was definitely causing a vacuum leak.
The engine definitely runs better at idle with the distributor vacuum hooked up, lol.

I'm still having some issues with rough idling, but I think it's just a matter of getting the idle and mixture screws set correctly now.

One thing I noticed during my research, and I'm surprised no one mentioned it, is my carb is turned 90 degrees from most others I have seen.
Most others have the fuel inlet in the front, with the throttle linkage in the rear.
Mine is rotated. The fuel inlet is on the engine side and the throttle linkage is on the fender side.

Do I have some sort of knock-off weber clone, or should I rotate the carb?

 

[Lumpy Grits]

Was not mentioned, as no one could see the fuel in the picture.
IF-That AF was removed, then it would have been a given.
The fuel line towards the exhaust header would lead me to think about vapor lock issues coming into play here.
You won't find many CJ's in in Ca. w/Webers, as they are not SMOG legal here..
LG

 

[dtrojcak]

Is vapor lock still a concern with a return line to the tank? I thought that was the main purpose of a return line?

Fuel lines going to the side instead of front were visible in first video.
Either way, should the carb be rotated?
All of the edges of the mounting plates line up with the grooves on the intake as if it's meant to be this way.

I'm in Texas, where we still believe in a lot of freedoms, so I have nothing to worry about Kalifornia's restrictions, lol.