Symptoms
Stalling, flooding, hunting idle, loss of power or running hot. Many of these are vacuum leaks or ignition faults rather than the carburetor itself.
The fix, step by step
- Moses Ludel's 4WD Mechanix guide says to diagnose before rebuilding.
- Check plugs, wires, cap and rotor, the vacuum and centrifugal advance, the PCV and every emissions vacuum hose.
- Mist penetrant near the throttle shaft ends at idle to find leaks.
- If the carb is the problem, record the idle mixture screw turns, strip it, and clean metal parts in carb cleaner.
- Clean rubber, plastic and electrical parts with alcohol.
- Clear the idle fuel pickup tubes, since a clogged one caused stalling in his example.
- Free the stepper motor's sticky rack.
- Set float height with a T-gauge, then the vacuum piston gap, metering rods, pump and choke to the kit specs.
- Refit with a new base gasket.
Tools & part numbers
- T-gauge
- hand vacuum pump
- timing light
- carb cleaner
- alcohol
- thread locker
- Mopar or Echlin/NAPA premium rebuild kit (Ludel's preference).
Where to buy the parts
2-barrel carburetor kit, 87–90 4.2L YJExtremeTerrain ↗Amazon ↗
Crown 83320007 Carter BBD carburetor with stepper motor, 82–90 CJ/YJ 4.2LQuadratec ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep Wrangler YJ 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.