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Ok, so i have a 1979 cj-5 with a 360 and a motorcraft 2150 carb 1.21

It does fine when i ease into the throttle slowly, but when i hammer it down and floor it, it stumbles and tries cutting out. When that happens, the jeep "bucks" and backfires through the carb. Does it need to be rebuilt or what? thanks
 

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Are you sure its "just" the carb causing the problem and timing also? I am a big fan and proponent of MC carbs and try to sell any one I can on the swap. I would bet money you need a new accelorator pump. They are really easy to change and you can usually get just the pump itself by ordering it from most any parts store. They wont stock just that part but will have a carb kit wich should be less than 30 bucks. I think a monkey with one eye could rebuild an MC carb. And if it needs that part it could prolly use a going through anyway.

To see if thats what needs replaced take the air filter off and look down the carb (engine off choke held open with a screw driver) and with your hand open the throttle linkage all the way open. You should see two squirts of gas come out of little jets above the venturi's. If you dont get two solid streams of gas squirted into the carb the problem is the accelorator pump. If thats not it you could have cracked venturi tubes. Those mean a whole carb replacement unless you have extras laying around that you can part out. Or a yunkyard that are not A holes and will part out a carb. PM me if you want o discuss further as I dont check here often.
 

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I have had this problem in the past. If you are using the stock motorcraft fuel filter, you may want to replace it with a new one. This was a fix for me on my mc2100.
 

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Ok, so i have a 1979 cj-5 with a 360 and a motorcraft 2150 carb 1.21

It does fine when i ease into the throttle slowly, but when i hammer it down and floor it, it stumbles and tries cutting out. When that happens, the jeep "bucks" and backfires through the carb. Does it need to be rebuilt or what? thanks
I would suggest you check your timing. Is your vacuum advance hooked up?
 

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i also have this problem with my jeep; i havent been able to solve it yet but i had suspected vacum advance or timing was out. you didnt mention distributer do you have stock ignition setup or HEI.

my motor is from 81 Chief and has all EGR blocked off and HEI distributer, fuel filter was replaced not long ago.
 

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Sounds like the accelerator pump isn't working. If this has just started recently, it's time for an overhaul. The parts aren't available outside of a kit. It's easy to take the carb apart and blow out the accel pump passages in case it's just a bit of dirt.
 
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