weber 32/36 on 258 i-6

mcgrnr0013

New member
hey guys i got a issue here and im not sure what it might be, first of all its a 89 yj with the 4.2 and a weber 32/36 carb. ive done the nutter bypass too. it just started a couple months ago when i was driving to work it did great while it was cold but after it got good and warmed up it got to where it would start bucking if i gave it too much throttle, and if i push it even further then it sounds like the jeep just turned off goin down the road. but i can let off the gas for a couple seconds and it will go back to normal for a second or 2 then it will start bucking. so im having to drive it around using less than half throttle, which makes climbing any steep hill difficult. it idles nice and smooth and it will rev all the way to redline without any problems. idk what it may be, the carb is only 1 year old the filter, fuel regulator, and fuel pump are less than a month old any suggestion
 
When was the last time you pulled the spark plugs? What do they currently look like? This will be helpful in identifing your problem.
 

the regulator is set on 4psi and the plugs looked pretty normal, the typical tan/brown IMG-20130723-00139.jpg color and #6 had a lil grayish i look but not bad the plugs are in order from left to right 6 to 1
 
So..... Let me ask a few questions. Do you have auto or manual trans? Do you recall doing any repairs or maintenance just prior to the start if your problems? When you say it will redline, you're reving it in neutral? With your current set up, does your fuel line split and return to the tank?
 

its manual and yes it will rev all the way to the redline without any misfiring or anything, it happened about a week after i regeared the rear axle, and about a month before that i had a bent intake valve that i had to replace. think maybe that could have something to do with it? the fuel lines are basically like stock only i have an inline regulator between the filter and carb, ive also checked the return line and it flows properly.
 
it seems like a fuel related issue, but i cant figure out why it does great after its been sitting for a while and after it gets warmed up it starts actin all crazy when i give it too much pedal for too long. i checked the carb float and it is functioning properly. oh and i also have 0 emissions hooked up only the pcv, the dist advance and brake booster are my only vac. lines hooked up
 
Very helpful info, sorry without seeing what you have this is kind of touch and go. With yours being a manual that eliminates interference from the kick down cable. When you rev it up, are you using the gas pedal or pulling the throttle lever with your finger? Check your linkage since it would have been disconnected for the valve replacement. With the engine off, have a helper slowly/fully depress the gas pedal while you check for the full range of motion. Pay close attention to the linkage (transfer bar) that connects the primary circuit to the secondary circuit (or primary venturi and secondary venturi). The transfer bar may have slipped the cotter pin or gotten bent during the repair. For a properly installed Weber, there would be no extra play left in the throttle movement when the pedal is fully depressed (i.e. when your helper has the pedal fully depressed you would not be able to move the throttle additionally with your finger). My next guess is you may have something clogging the internal circuit like a blocked E-tube, secondary jet or even the primary jet which will cause a delay or “bridging” during circuit transition. Or it may be a mal adjusted fuel float. Just keep in mind that you will likely need a rebuild kit if you open the internals of the carb.
Another possibility, although less likely, is you have a leak at the intake manifold gasket. Consider that you have a cast iron block and an aluminum intake. When you replace the intake/exhaust gasket, did you use both pieces of the gasket? I know some folks disagree but the smaller silicone gasket serves a propose.- Just a though, but if you have such a leak you would likely have other problems as well.
When you “re-geared”, did you go higher (towards 2.73) or lower (towards 4.88)?
Lastly, and this is not likely contributing to your current problem, but Webers do not like a OEM style fuel return. There are ways of making this work properly and to your advantage. They were designed to operate on a straight, consistent fuel feed at ~4psi. They also develop problems from the pulsing of the mechanical fuel pump. But that is a discussion for another day if you’re interested.
Keep us posted!
 

When I regeared I went from 3.08 to 4.11. And I am positive that its not an intake leak because I used both gaskets and had problems with a air leak so I took it back off and put rtv around all the intake ports. When you say linkage are u meaning the linkage going from the pedal to the carb or the linkage between the primary and secondary barrels?
 
im considering buyin a new carb since this one is already giving me troubles, any recomendation as to which would be best for it, motorcraft 2150, weber 38/38 or like one of the holley 2barrel?
 
When I regeared I went from 3.08 to 4.11. And I am positive that its not an intake leak because I used both gaskets and had problems with a air leak so I took it back off and put rtv around all the intake ports. When you say linkage are u meaning the linkage going from the pedal to the carb or the linkage between the primary and secondary barrels?

Check all the linkage, there should be no excess travel anywhere. Pay close attention to the linkage between the barrels, it can bind and come lose but may "look" to be in tacked.
 

im considering buyin a new carb since this one is already giving me troubles, any recomendation as to which would be best for it, motorcraft 2150, weber 38/38 or like one of the holley 2barrel?

Be a Weber fan with many years experience with them, my vote is always going to be for a Weber. Unless you have some type of mods to your engine (like headers, ported heads, bigger cam, higher compression or some combo of these) the 38/38 will not perform like you want it too. It this point you may want to rebuild the Weber you have and look for an internal problem. Even if you swap to another carb you would get more money on a re-sell of the existing carb because its been freshly rebuilt.
 

Okay awesome. I'll order the kit tomorrow, and will let yall know how it all goes. And I also want to thank all the people helping me out especially policemonkey161. You've been a huge help
 
Ok I rebuilt the carb with no luck. Although I did find a little trash in the accelerator pump diaphram and the full power valve tube was blocked. But I think I found where the problem is. I believe the filter on the fuel pickup tube is getting stopped up because I can blow air through it with the air compressor and it'll drive fine for a while. So I'm goin to pull the tank take the sock off and put a clear inline filter right in front of the pump.
 
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