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-   -   81 CJ7 Carter BBD To upgrade or not to upgrade? (

KnoxButler 06-24-2013 01:38 PM

81 CJ7 Carter BBD To upgrade or not to upgrade?
Hey guys I made a previous post about an engine flutter I had been having. After preforming a "Team Rush" Upgrade and getting positive results but not much improvement with the idle flutter and doing some research I deduced that my problem is probably coming from my Carter carb. (I believe it is the version without the stepper motor)

From what iv seen, it appears as though my choke isn't adjusted properly and I'm willing to bet that the mixture screws are way out of whack as well. It seems that my jeep might be idling a little low causing the engine to be closer to the edge resulting in the flutter I'm feeling. Besides the whole thing could probably use a rebuild and clean up regardless. Also most of the vacuum lines to the carb. are cracked and old or non existent.

My question is... is it worth putting in the time to do the maintenance on this carb. to get it running smoothly? I have read that these carter carbs. can be inconsistent in there performance and if I'm going to have to do a tune up and run new vacuum lines anyway I thought it might be a good time to just upgrade to a new carb. instead. If so which one should I get?

Thanks guys!

walkerhoundvm 06-24-2013 02:04 PM

What are your emissions laws like where you live? To me, that would be the first answer I'd need to make a decision. Secondly, are there rumors of stricter emissions laws in the future?

The year after I bought my CJ, northern Colorado put into place stricter emissions laws. I was stuck with a 4.2 with all sorts of modifications - intake, exhaust, carb, etc. So while it was legal the first year after I registered it, the next year it wouldn't come close to passing emissions.

Had to go with a Howell kit, and even then emissions raked me over the coals.

I liked my MC2150 while I had it, but if I had it to do over again with hindsight, I either would've went right to the Howell kit or found a drop-in 4.0.

KnoxButler 06-24-2013 02:37 PM

I live in Tucson AZ. I'm not sure if they are strict or lenient because I dont have anything to compare them to. Here is a link to a pdf. which shows the requirements etc. I believe that my Jeep falls into the "Non-Diesel 8500 lbs or less GVWR" class third from the top and im located in "Area B"

It would be important for it to allow me to pass my local emissions.


KnoxButler 06-24-2013 02:40 PM

UPDATE: It seems that my carb. is struggling to keep a proper fuel to air mixture. When it is idling I can choke the carb. way back and it will smooth out, but as I rev the engine the valve stays the same and the engine chokes because of the lack air coming in. I don't know if it should be this way but, if i open up the valve so it gets enough air at high rpms it wont return at all either and the engine sputters at idle?

Any ideas?

CJ7_Jim 06-24-2013 04:13 PM

Knox, see if AZ will allow carb swaps.
I'm in CA and they won't let you use anything but the crappy carter that comes stock.
That's why I went with the CARB approved Howell EFI.
If you can, swap out for a motorcraft 2100 or a weber carb.

Balvar24 06-24-2013 04:23 PM

I have a Carter. I've had no trouble with it.

KnoxButler 06-24-2013 04:39 PM

Im willing to stay with the carter, I just dont know how to adjust it so that it works properly. Anyone have any pictures, videos, diagrams, or any instructions etc. that would help me tune it up, specifically all the screws and adjusting the choke?


LumpyGrits 06-24-2013 04:41 PM

FIRST, does the AZ. county you live in require smog tests?
IF, YES------You're screwed, and will have to get the Carter run'n 'rite'.
FWIW: I live in PRK, and have to still play the 'smog-dance' with my '85.
I'm still run'n my Carter.

CJ7_Jim 06-24-2013 04:52 PM

If you're going to keep the carter BBD, you'll need to replace any of your vacuum lines that are cracked.
Also, have you checked the idle tubes in the carb?
They are notorious for getting plugged.

KnoxButler 06-24-2013 05:26 PM

- Grits: Ya, Tucson does require smog tests I believe. Iv already been planning on replacing the vacuum tubes, just trying to work through the diagrams... As for getting the Carter running right that's what I'm really struggling with, I have no basis of knowledge of how it should look, run or really the processes of tuning it.
- Jim I have heard someone else mention the idle tubes, venturi right? How would I go about cleaning them out?


CJ7_Jim 06-24-2013 05:31 PM

Hey's an easy fix.
Start here:
You can google carter bbd idle tubes fix and find all kinds of info on it.

CJ7_Jim 06-24-2013 05:34 PM's another great site to bookmark:

LumpyGrits 06-24-2013 05:39 PM

You REALLY need to get a copy of the Factory Service Manual(FSM)and read it from cover to cover.
This may help also.......

KnoxButler 06-24-2013 06:17 PM

Thanks guys, Ill look into all that and report back!

86cj74.2L 06-24-2013 08:12 PM


Originally Posted by KnoxButler
Thanks guys, Ill look into all that and report back!

Take some pictures of your carb and how the choke is setup.

The time now is 12:31 PM.

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