Carter BBD Rebuild issues

Maine Cabin Man

New Member
Joined
Oct 15, 2025
Messages
3
Location
Greenbush, Maine
I have a 1987 YJ 4.2L
I rebuilt the carb due to a vacuum leak. After I put everything back together I adjusted both mixture screws to 2 turns out. Originally, they were at 4.5 and 3.5 turns out. It started fine. It warmed up, I set idle to 850. I thought this was going great! I took it out for a quick test drive. It spit and sputtered some but when I decelerated from 3 to 2, it started backfiring...bad... It stalled. Now it's idling rough and barely idles at 500. Sounds like the timing is off or I lost a plug or wire. Any suggestions on what is going on here would be appreciated. Should I turn the screws out a little bit?
 
Take the plugs out and see check the color or if they're wet with fuel. Sounds like something got loose with the spark if it was running good then got worse. Is the distributor cap and wires tight?