Symptoms
Stumbling, sputtering or stalling at idle and poor fuel economy, but running fine at higher rpm. Offroaders.com says the cause is almost always clogged idle tubes, which let fuel drip from the venturis.
The fix, step by step
- With the engine running and choke open, look down the throat.
- Fuel dripping from the idle nozzles confirms it.
- Remove the air cleaner (tag every hose), the choke plate and rod, then the two screws and the venturi cluster.
- Check the idle pickup tubes are seated, clear the tubes and nozzles with fine wire and carb cleaner without dislodging the check ball, and reassemble.
- Tighten the carb body screws, which tend to loosen.
- For a longer-lasting fix, the article suggests drilling the idle tubes to 0.032 inch.
- Pre-1979 sixes use a one-barrel Carter YF.
Tools & part numbers
- 3/16 in socket
- small screwdrivers
- carb cleaner
- fine wire
- 0.032 in drill bit
- Crown 83300057 kit for 1973–78 YF carbs
Where to buy the parts
Carburetor repair kit, 1979 CJ-5 4.2LRockAuto ↗Amazon ↗
Crown 83300057 carburetor repair kit, 1973–78 CJ 6-cylQuadratec ↗Amazon ↗
Weber K551-38-S 38 DGES carburetor kit, 1972–90 CJ 4.2LQuadratec ↗Amazon ↗
Holley 550-859 Sniper EFI BBD (258 six)Quadratec ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep CJ-5 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.