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Okay so I just picked up a Jeep YJ, I previously owned a ZJ with 6”lift, 35s, new solid steering and some other mods which I’ve done myself. I have a decent mechanical background but not any official schooling.

The reason I am telling you all this is because tonight my wife and I picked up an 1988 YJ and when I first went to look at it it was running totally fine, it has a new carb, new plugs and wires, new battery, new alternator, and some other newer parts. The Jeep ran fine at idle, it even test drove okay. So I bought it and then took it for another little test drive with the wife. We didn’t go more than 50km/h and only drove about 5kms when it just sputtered and died. The Jeep wouldn’t start. Gave it some throttle and got it to fire up but it ran super rough and would not idle. So I figured the carb needed to be adjusted, thought maybe it vibrated loose? So I turned the idler screw to increase the idle speed. And it worked I could start the Jeep and it was idling on its own but not well.

I was just about to hop in and drive it back home and noticed a ton of smoke coming from underneath the Jeep. I bent down and saw that the catalytic converters was glowing red hot so I immediately shut it off and called the tow truck.

I got it back in my driveway and there was coolant all over the flatbed. There’s still oil in it but I didn’t have enough time to see how much coolant was lost. When I was driving it the water temp never went above 170 so it shouldn’t have over heated?

I am not too familiar with carbureted engines so if anyone can give me some insight as where to start?

Jeep is 1988 YJ 4.2L auto trans, basically stock, no mods other than bumpers and a winch.
 

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If it still has the Carter BBD carb, it's very likely that the emulsion tubes got plugged with dirt or rust from the air injection system. If plugged, the engine will run very rich at lower engine speeds and won't idle unless the throttle is opened more.

Even a new carb can be quickly plugged with dirt, carbon and rust from the pulse air injection system. It's air intake tubes are inside the air filter element so any crap coming out of them from failed valves or a plugged cat converter enters directly into the carb opening. The dirt will get into the carb bowl and get into the emulsion tubes and plug them.

If this is what happened, the only way to fix it after cleaning out the carb fuel bowl and emulsion tubes (Keeping it stock) is to replace all of the AIR tubes and valves. This will last maybe two or three years before they rot again. Bubba would simply plug the air ports inside the air cleaner, but that's not smog legal. The best way is to ditch the carb and install EFI, a smog legal one if that's needed to pass an emissions test in your area.
 
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