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One possibility, its not tuned for your rig.

Jetting, tuning, CFM need to match properly.

Another idea, could be a vacuum leak or something not hooked up that once was with the old carb.
 

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If its running rich, you will need to find someone who knows what to do. Changing the plugs may help it run better for a bit, but will not fix the problem.

Its not difficult really, carbs are really a dumb air fuel mixer; but finding someone who works on them is getting harder. I for one like them because they are easy, and if you are willing the internet and I could help you walk through it.

Basically, assuming you are right in it running rich, then you basically need to get new jets. If you do a search you should be able to find the sizes available and a starting point. Once you find out what you have, step down in sizes, one size at a time then go run your jeep. Once the plugs come out the proper color (milk chocolate brown, to light brown) then you basically have the mixture right.
 

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also just read that part of the running rich could be too much fuel pressure; you could try to put in a fuel pressure regulator and set it to 3 lbs and see if that helps.
 

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no, Jets are typically carb specific.

Start with the regulator, and with new plugs check for the color. If you get a light brown/tan then you're as good as that gets. But if they are black then you need to re-jet. At that point is where you would verify what you have, and buy a few sets smaller. They should be fairly cheap, between $4-$6 a pair.
 

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Ok ill get some info on tuning the carb. Its a Weber k551 from quadratec. It runs awesome down the road as is, about 1300 rpm at 55. But I hope with this great information and a Nutter bypass I should be even better
Im assuming that is a 3speed auto?

If so, I believe 1300 at 55 is a bit low; the 4.2 is a torque motor, but honestly it likes a higher rpm at speed. More like 1800-2000 would be better at 55; not that it cant do it, but lugging the motor like that can also drag down your mpg.

BTW, did you change into those tires before your last mileage check? I would suspect your odometer is off unless you changed the speedo drive gear.

I just ran a gear ratio calculator and it suggests your speedo is off. At 55, assuming stock gear ratio and the 35" tires, your tach should read about 1800 at 55; otherwise your gear ratio is 2.5 which was not an option on the Wranglers.
 

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Yeah. Im headed to the parts store for a pressure regulator and some jets and a new inline fuel filter now. Im hoping to see something over the 15 I was getting while it was blowing black smoke and leaking all over the place
Im thinking the regulator will help a lot; and then if you want to check for the jets.

You should verify what you have for jets before you go buy them, if not you have a chance of getting the same ones again. Not to mention, the parts store will probably not have them in stock.
 

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I just got back from the parts store with the regulator plugs and filter. When I went to leave the Jeep wouldn't fire. First time I've ever had that happen. I tried for about 5 minutes with no luck. Finally put it in neutral and rolled it down the hill and it fired up, blew a big cloud of smoke and the whole way home the tach said 1800-2000 @ 55
Thats what the calculator said using the standard equipment axle ratio of 3.55

But your starting issue leads me to believe there is too much pressure or a leak causing gas to dribble into your cylinders. Basically, it flooded out while sitting there.
 

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crankcase pressure, not to worry, it happens. But to be sure all is good you can check your PCV valve and associated hoses and make sure they are clear.

Now that its running good, take it out for about 15-20 min drive then check the plugs for their color.
 

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Well, honestly until you find out why its dying, just replacing things can end up expensive and still not correct your issue.

At this point it looks like youve gotten better, but it still could be carb, or ignition, or?

What color did the plugs end up?
 

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The plugs looked to be fine ..just a little brown on the end. The carb is a brand new one and I had it installed and tuned but im not sure where to go next because it just dies randomly. I really don't want to waste money replacing stuff that doesn't need to be. The MPG has gone up to 12 though
What I mean is, it could even be the new carb; like sticky float or needle and seat issue. Float may not be set right even, just because it is a 'new' carb does not mean it will be free from issues. its also possible your fuel pump picked up something from the tank and is playing havoc on the filter or carb.

Nice to hear about a bit better MPG, and I would expect to see about 12 myself. Its even possible to run midgrade or even premium gas and get a mile or two extra.

Dying randomly makes me wonder... Check your gas cap, I have accidentally used non vented caps and that caused a similar problem; or even the vented cap could clog. Can you describe what happens when it dies? Does it die with no indication or does something change in performance, in engine sound, or something like that? When you restart it, does it fire off immediately with no extra help from you? (like a pump on the gas pedal) How long can you typically go before it acts up?
 

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It will sputter real quickly and die like it runs out of gas but as soon as I put it in neutral and turn the key it will fire back up while its still rolling. It has only happened a couple times this week and the carb has been on about 3 weeks. I ran seafoam through the tank about a week before I changed carbs if that could have made a difference.
I would lean towards a fuel issue then. Seafoam can clean out the goo, but if there is something like rust in the tank then the filter could be getting clogged (or some such) and seafoam wouldnt be a help.

You may have a clogging filter, bad fuel pump, sticky float or still have a leaky carb problem. Or even that gas cap issue.
 

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Well, not sure I would start with that, but its as good as anything I suppose.

I really think you need to find the problem before throwing parts at it.

Did you have the new pump with the old carb, and did it do this before any changes/ new carb?
 

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Gotcha... Yeah, at this point without being able to stand in front of it and check things, it will be hit and miss on what the diagnosis will be.

Hopefully Im not steering you off track and it not be a fuel problem.
 

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Nah you're not at all. Any help I can get is greatly appreciated. I just wish that there was a decent Jeep place around here I could take it to.
Actually, you just need a good old school mechanic. :)

Carbs are much easier to deal with, IMO, but schools/training are not exactly teaching how to work on them anymore. Its mostly R&R, and basically hope the rebuild shop did it right.
 

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Nice, but that popping noise seems interesting. You may have some unburnt gas or something in there.(shouldnt be, but hard to say)

Or it could be just expansion and contraction from heat and cooling; thats typical.

Take it on a decent drive yet? That would help some since youve been pumping a lot of gas through the system, and it should get cleared out.
 

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I suspect then you should have cleared out that exhaust system by now then. Not sure I would worry about a popping in the muffler, unless it got worse or the Jeep was running poorly.

If your spark plugs are the light brown, then your adjustments are pretty good on the carb. Of course it doesnt hurt to check and verify timing and the like, but generally adjustments like that do not affect the muffler.
 
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