Introduction: Fix Idle and Stalling Problems on a Jeep Cj-7 or Wrangler Yj

About: Studying mechanical engineering at UNR.

Jeep Cj-7's and early wrangler YJ's with 4.2 liter engines came with a rather lowsy carter bbd carburetor which of goes out fo adjustment. One of the most common problems with this carburetor is an erratic idle; in extreme cases (as it was with my jeep) the vehicle will stall every time you slow down or stop.

This instructible gives an easy fix for this problem which will make the carburetor operate as well (or at least close to as well) as it did when it was new and can be done in 30 minutes to an hour with the carb on the vehicle and with only minimal tools and a can of aerosol carburetor cleaner.

This process should work for about nine out of ten people with this problem, and if it doesn't work for you, it probably means that you need to do a complete carburetor rebuild.

Note: this is my first instuctable so give me some slack, and I will try to add more pictures/videos soon.

Step 1: Gather Tools

All you really need for this project are some basic tools, and a can of carburetor cleaner .

You need:

1. Flat head screw driver
2. 3/16" wrench or driver
3. 1/4" wrench or ratchet
4. Pliers
5. Carburetor cleaner (not shown; any brand from an auto part store should work)
6. Air compressor with 'blowgun" attachment. (not required but highly recommended)

Step 2: Diagnosis

If your jeep stalls when you slow down or stop, or even just acts strangely when idling, this process will most likely help or fix the problem in only about 30 to 60 minutes.

The easiest way to tell if this will help your jeep is to start the jeep with the air cleaner off, once you have done this, open the choke and look down into the carb, if you see any dripping off either of the jets this instructable should help or fix any idle problems you are having, otherwise you may need to rebuild your carb or look into other problems.

Step 3: Remove Air Cleaner.

Remove the two wing nuts and remove the top of the air cleaner assembly. At this point, you should also use a pair of pliers to carefully pry of the metal "loop" over the carburetor that holds down the air cleaner. (i forgot to do this until a later step, but it is best to do this now).

Step 4: Remove Choke Assembly

Note: I forgot to remove the wire from step two until later, but it makes this step easier if you have already done this.

1. Remove wire clip from throttle linkage side of carburetor (see picture)
2. Remove 1/4" bolt from opposite side of choke rod (see second picture) and remove little flange thing the bolt held on (you may need to tap it with a screw driver, or something similar)
3. Remove the two 3/16" bolts holding the choke plate onto the choke rod (depending on your carburetor you may have small flat head screws here, but still remove them) Be extremely careful not to drop these screws into the carburetor, or you will have to spend quite a while "fishing" for them!!!
4. At with all of this removed, pull out the choke rod; the choke rod should slide out of its holes easily.

Step 5: Remove Venutri Assembly

The venutri assembly is a small assembly which is the cause of all of your problems (I really do mean all of them [At least the ones related to your carburetor idling badly]).

At this point, you should be able to look into the carb and see two screws with holes in the heads, you need to remove these (be careful not to damage them, they are important).

After removing the two screws, you should be able to lift out the venutri assembly in order to clean it.

Note: the assembly will have two halves, the top one having two pins sticking out; be careful with these, although they are the primary source of clogging in this carburetor.

Step 6: Clean Everything

Once the Assembly is out, spray all of the holes with the carburetor cleaner, paying special attention to the long pins on the upper part of the assembly. (it is best to use a long thin piece of wire to break up any blockage in the pins.


Once you have done all this, carefully blow out the remaining cleaner with a low pressure air gun, pay attention to my warning above for this part.

Step 7: Reassemble

At this point, all you have to do is undue steps 3-6 in reverse order. Once you have reassembled your carburetor, fire up the vehicle and you should immediately see a difference, if you don't see a difference, you can either try and repeat the process, although that would mean that you likely need a complete carburetor rebuild.