Symptoms
Stumbling and sputtering at idle, stalling at stop signs, poor fuel economy, or an idle that someone has turned up to hide the problem. Offroaders.com says the most common cause is clogged idle tubes letting fuel drip from the venturis, so it runs rich.
The fix, step by step
- With the engine idling and the choke open, look down the carb: fuel dripping from the venturi nozzles at idle means the idle tubes are clogged.
- Engine off.
- Remove the air cleaner (tag the hoses), the choke-plate screws, the choke-rod clip and screw, then the two screws holding the venturi cluster, and lift it out with its two gaskets.
- Spray everything with carb cleaner without dislodging the center check ball, clear the idle tubes and nozzles with fine wire, and reassemble with every body screw tight.
- The article says Jeep once recommended drilling the idle tubes to 0.032 in to stop them clogging again.
- If it still idles badly, look for split vacuum hoses and intake leaks before blaming the carb.
Tools & part numbers
- Screwdrivers
- snap-ring pliers
- carb cleaner
- fine wire
- masking tape for labeling hoses.
Where to buy the parts
Carter BBD rebuild kit & gaskets, 1983 CJ-7 4.2LRockAuto ↗Amazon ↗
Weber K551-38-S 38-DGES carburetor kit, 72–90 CJ/YJ 4.2L (replacement option)Quadratec (Weber) ↗Amazon ↗
Holley 550-858K Sniper EFI BBD master kit, 71–86 CJ 258 (EFI option)Quadratec (Holley) ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep CJ-7 parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.