sputtering under acceleration

B.B.D.

New member
84 cj w/ 258 , weber 32/36 dgev carb. new fuel pump and filter with no line obstructions. idles fine but when accelating in gear it acts like it's running out of gas untill i get out of the skinny petal and a few seconds later it clears it self up and idles fine again. the weber guides says......locate and remove the primary idle jet holder { what / where is that ?} remove the jet from the holder { does it screw out ?} hold up to a light and check for roundness of cavity. remove the idle mixture screw from carb and blow compressed air through the two openings and re install........ i've never tore into a carb before but i'm not against it. any suggestions or hints ? thanks.
 

does the weber have an accelerator pump? That might just need adjusting.
 
Where the overtravel arm connects to the throttle, there should be a little nut or some similar thing on there that lets you change the length of that arm. If you make it shorter, it will give less gas upon acceleration, which is what I'm thinking you probably need to do. I'm basing all this on my Motorcraft carb experience now, so I may be wrong. If you've been running this carb for a while and it just started doing this, then I am probably wrong, but this is just my best guess. Let's see if somebody with a little more Weber experience has anything to say.
 

well i tore into the carb , taking the brass screen out , taking the top of the carb off and the jets out and everything else that would screw out. i brought all the parts to the bench and cleaned em then blew em out with the compressor, put it all back together and it ran great. i replaced the fuel pump and filter cause i smelled gas in the oil so i'm gessing that a part of the rubber seal in the pump came off and got caught up in a jet or somewhere. it's running great now { at least till next time }
 
i wouldn't say you were no help, if it acts up again i'll have another thing to check out. thanks for the reply.
 

well it's still going on. again i tore into the carb , taking it apart and cleaning it and reassembled it [again]. the weber guide says as a last resort i should check the fuel tank venting system and to check a shop manual but my chiltons doesn't say how to . so how does one check a venting system ? nothing seems to be obstructing it.
 
anyone ever have a problem with the liquid check valve on the tank venting system ? the tank i have is from a 79-81 and the check valve is fed from 2 lines from the tank and has a outlet that goes to the charcoal canister. i'm thinking that if the check valve is shot and possibly stuck then that could have something to do with the motor being starved for gas on acceleration ? anyone with any input ?
 
Check your fuel pump. The manual pump on the 258 is cheap. $30 something at Kragen. I had the same issue with my 88 YJ with the 258. I replaced the fuel pump and it solved my problem.
 
so i bypassed the fuel check valve completely and even though the problem is slightly better it is still happening. it's not as bad as it was before , so far anyways , but it still happened. so as a recap........ carb torn down and rebuilt multiple times { once while on the phone with weber }, fuel pump replaced, new fuel line , new glass fuel filter , good gas , check valve bypassed , no vaccume leaks { as much as any cj can avoid them } carb mixture right where it should be and timing is set about 4 degrees advanced , coil pumping out lots of spark. what else is there ?
 
what if it's a valve problem ? could one be stuck or even bent , screwing up the fuel going into the cylinders ? even if i was only running on 7 of em it doesn't explain why it idles great or would it ? doesn't ANYONE have a answer ?
 

I don't think anybody has any ideas. This is strange. Are you absolutely SURE the carb mixture is set right, because it really sounds like you're running rich to me. Make sure the choke linkage isn't binding or anything.
 
the plugs are burning clean and i even wired the choke open after it had warmed up just in case it was closing for some reason . man , i'm telling you guys i'm startin to go nuts cause i JUST CAN'T FIGURE THIS OUT !
 
ok, at idle my tach was bouncing between 600 and 850 so thinking about SENORCOLES post i started screwin with the carb { again ] . 4 half turns out it started skipping so i went back in 1 half turn and it idled fine , this was the first time i noticed anything at idle . took it for a rip down the street { about 1/4 mile } and ran great untill i turned around and as i was about to get on the gas it hesitated but cleared up right away . went down another street about 1/2 - 3/4 mile and stoped for a stop sign . when i started again it was a hard left and the motor stalled and started again fast enough to chrip the 33s but then ran fine . as i started up my street , uphill , it sputtered a few tims and cleared out then ran fine for the 1/4 mile or so to my house. i don't think it's a valve issue anymore cause it's not constant . it's got to be a fuel delevery problem ya think ? as a cj owner i know that crap breaking down comes with the territory , i mean these things had problems right out of the factory , that's just the way it is with these mechanical time bombs { said with lots of love } . i've been a jeep owner for almost 20 years with 3 cjs and a 72 commando but this one is getting the best of me and it's my favorite one so far. somethin's gotta give.
 
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allright , so i've been thinkin . i ordered a new vacume advance today. if it's not working properly then under acceleration i'm not getting the proper spark and it would cut out right ? when i get off the gas it clears up but maybe not because it has anything to do with the gas supply but instead the spark aint hittin when it's supposed to and then has a chance to catch up . when i get off the gas to turn around it sometimes sputters but maybe not because the gas is f ' ed but the spark can't adjust itself fast enough . i took the vac. advance off the dist . and even though it will move it's harder to do { manualy } than a sonofagun . i took the vac. line off the carb and put it right on the intake manifold but like i said , it is tough to move , i would think i'd need a TON of vac. to move it . we shall see.
 
Don't know, but have you checked your float bowls? The reason i ask is because i had a lot of problems with holly's on this . Does Weber's have them?
 
When I was working on my ignition, I remember my vac advance was a PITA to move as well. Soo, don't think that's it, but I guess it's worth a try.
 
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