4.2 sputtering

J

Jeepster05

New member
hard top and doors for YJ

I rebuilt my carburetor 2 weeks ago and now I get worse gas mileage and the thing is sputtering when it actually idles and when I'm on the gas. I can feel a large loss of power. It might be the cold but I don't think it would run so bad just because of a little cold. Anyone had this problem?? oh and it is a carter.
 

Well one possibility could be that you have it set too rich. That would cause the gas mileage to go down and could also cause it to sputter if you are flooding it. Have you tried to adjust the mixture to the highest RPM. It could also be a vacuum leak. So check the base gaskets and all vacuum lines. The only other thing I can really tell you would be to replace the Carter. They are not very stable carburetors. They have to be in perfect condition and adjusted perfectly in order to work.
 
UPDATE: 4wd problem after lift

I changed mine out with a Webber carb and still having problems setting it.
but i think there are still some vaccum leaks or something i am missing.

good luck
 
i am having the same problem (always have since i got this jeep). dont waste your time adjusting the carb, i adjusted my weber for hours for nothing. also adjusted the timing over and over, advancing and retarding with no luck. i installed the tfi upgrade and that allowed me to rev past 3000, but gave me no power increase. now im gonna bypass the computer and replace all the vacuum lines (as soon as it stops snowing!!!!). if you get her figured out let us know and i will do the same :D
 

That is something I have heard alot of people say about Webbers. Don't get me wrong they are good carbs. but they have a tendency to be difficult to tune. You need to get it just write. That is why I got a Motorcraft 2150 (1.08 size). I did alot of reserch into it. They are very stable. It will still run great even if you tuning of it is way off. I know mine is running really rich right now. It need a new thermo, it only reaches 180 degrees. It too cold to fix it now. It runs really great anyway though. The only thing is I am only getting about 12 MPG. It need adjusted pretty bad.
 
I just put a 400cfm Webber on my 86 258 and talk about run rich and sputter. Fortunately I have a friend who is a gifted mechanic. Anyway turns out the float was set too high from the factory. Pulled the cover off, tweaked it back just a hair and it runs like a champ.
 
i was having these problems before and after the weber conversion, so i dont think that it is a problem with the carb. it has done the same thing with the carter as it does with the weber, except it actually idles now :D ....
 

If you suspect a vacuum leak, here is a great tip I got from my carb guy to check.
Take a clean 2 liter bottle, fill it with water, drill a small hole in the cap, and when the engine is running spray the water at the base of the carb and the intake manifold. If there is a leak you will know it by the engine dying or the sucking sound. Make sure to cover the intake of the carb to keep the water out.
 
When rebuilt properly, adjusted and installed correctly just about any carb will feed a factory 258. I had a 232 with a 1 barrel and it ran fine. In past experience, I have had two carbs work extremely well on 258s without extensive tuning and with minimal hassle. For a factory engine you really can't go wrong with the bigger motorcraft 2150. For a built engine, I always recommend a Holley 390cfm 4bbl. and a Clifford intake.

I think the Carter carb is like the two piece axles in the AMC20 rearend. They are both actually good units and perform great when they are brand new and in perfect condition, but after a little wear and mileage they become junk and the best fix is to just replace them with something better.
 
I just got a weber from a friend. Paid $189 to have it rebuilt w/lifetime warranty. Put it on my 258 and it runs great now. The only problem I have was routing the distributor advance vacum line. I had to search around but found the correct one on the cto that did the job. Before that mine engine would spit and sputter.
 

Would you mind how you connected the vacuum advance to the CTO. I just got a weber carb and seems like I am having the same problems. And help would be welcome and much appreciated!


Alex
 

If you suspect a vacuum leak, here is a great tip I got from my carb guy to check.
Take a clean 2 liter bottle, fill it with water, drill a small hole in the cap, and when the engine is running spray the water at the base of the carb and the intake manifold. If there is a leak you will know it by the engine dying or the sucking sound. Make sure to cover the intake of the carb to keep the water out.
Click to expand...
That's a bad idea. I can't believe a mechanic told you to do that. If it has a vacuum leak then it will suck the water in the engine anyway. I have used WD-40 in the past and have seen other people use carb cleaner for this trick.
 
re

I agree with redrooster. Why would you allow the vacuum to suck something bad into your engine like water when you could use something harmless like carb cleaner? Instead of making the engine die with water, using a volatile will make the engine surge. It just seems to make more sense to me.
 
I guess youre right, I didnt figure this guy would BS about it as he has a Carb shop with a great local reputation and has helped me get my Carter BBL running pretty smooth and reliable.
 

Body Lift

Well, I am in no position to question anybody with any experience because I have none. :D I am sure there is a good thought behind that technique.
 
Here is how I hooked up my vacum lines with my weber to my CTO on a 88yj with a 258. Keep in mind I do not have any emmisions on my jeep. Not required in FL.


CTO Diagram facing the engine.
1) 0
2) 0 3)0
4) 0 5)0

Connection one is closed. Nothing hooks up to it.

2 & 3 are tee'd together and then hook to the side of my carb.

4 goes to the canister on the drivers side fender wall on the first plug.(the one closest to the tire or front end of jeep) This gets alot of suction. You probably can tap your emmisoins into this line.

5 goes to my vacum advance on the distributor. No other port would allow my jeep to run properly with the vacum advance. Hope this helps you.
 
I am gald it wasnt just me.
lets us known about the vaccum line from the distributor.

i am going to go over all the possible vacc lines agin and have the butterfly/ choke settings checked agian.
 

they way I just poste up above is how I run my vacum advance now. It works great.
 
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