Carb Issue or Not?!?! NEED SOME HELP!!!

[musciab]

76 CJ5 – AMC 258 i6 / 4.2l I6 unsure of the carb but I am assuming it is stock 1BBL: Still kind of new to the CJ world. I have already pulled my engine to replace my clutch (easier than having to cut the welded skid plate off the frame from the PO) and have been slowly replacing worn and damaged parts. Currently the engine is back in and running OK, but I am having some issue with what I think is the carb. So starting my CJ is normally not an issue and really hasn’t been, it’s a hard sleeper if its been a few days but not too bad. I have a manual choke and rarely use it. Taking off in the morning, it runs decent, prob needs a good tune up, but my issue come up when it gets warm and I have been driving for 10 mis or so, I go to take off from a stop sign or light and I get some sputtering and/or what seems to be a backfire almost stalling it unless I get on the gas, and gets worse as I drive more until it cools down. Does anyone have any idea of what could be the issue. I need to get this lil guy ready and road worthy asap. Thanks for the help in advance.

 

[IOPort51]

vacuum leaks.

76 CJ5 – AMC 258 i6 / 4.2l I6 unsure of the carb but I am assuming it is stock 1BBL: Still kind of new to the CJ world. I have already pulled my engine to replace my clutch (easier than having to cut the welded skid plate off the frame from the PO) and have been slowly replacing worn and damaged parts. Currently the engine is back in and running OK, but I am having some issue with what I think is the carb. So starting my CJ is normally not an issue and really hasn’t been, it’s a hard sleeper if its been a few days but not too bad. I have a manual choke and rarely use it. Taking off in the morning, it runs decent, prob needs a good tune up, but my issue come up when it gets warm and I have been driving for 10 mis or so, I go to take off from a stop sign or light and I get some sputtering and/or what seems to be a backfire almost stalling it unless I get on the gas, and gets worse as I drive more until it cools down. Does anyone have any idea of what could be the issue. I need to get this lil guy ready and road worthy asap. Thanks for the help in advance.

 

[JR74CJ5]

Mine used to do that...

If I hit the gas when coming to a stop in nuetral it would stay running, otherwise would spit, sputter and die.

For me it was a broken linkage on top of the carb. I would remove air cleaner, and look over everything.

Start looking for broken linkage on the carb, or as IO suggested vacuum hoses that appear to be cracked, or disconnected.

If you see some with plugged ends, they may not actually be the problem, just start with what is uncapped or hooked up first. Look everything over real good.



~ JR

 

[musciab]

I guess my situation is a little different, its not so much coming to a stop, its taking off from a stop. So say I'm at a stop sign, start letting the clutch out and start giving it some gas, the engine starts to pop, spit and sputter a little unless I over rev it but then just after I let the clutch all the way out it will backfire. This is only the case when it gets warmed up though. Also, say I'm driving down a straight road going 25 30 mph, you can hear it spitting a little, it goes away a little when I get moving a little faster. So I dont know if it would still be a vacuum leak or what you said, "broken linkage". Could you maybe elaborate a little on what you mean. should I look for just anything broken or am I looking for something specific that could be doing this.

Just to give you a little more info, my carb has every vacuum cut and plugged, or atleast I think all are plugged. When I get home today I can take a pic of it and post it if that might help.

Thanks guys. I kind of feel like I'm back in college taking a class in "How to fix and trouble shoot your Jeep"!!! Haha, thanks again.

Mine used to do that...

If I hit the gas when coming to a stop in nuetral it would stay running, otherwise would spit, sputter and die.

For me it was a broken linkage on top of the carb. I would remove air cleaner, and look over everything.

Start looking for broken linkage on the carb, or as IO suggested vacuum hoses that appear to be cracked, or disconnected.

If you see some with plugged ends, they may not actually be the problem, just start with what is uncapped or hooked up first. Look everything over real good.



~ JR

 

[OEM1984CJ7]

Mine kinda does the opposite. It idles fine but when under a load or accelerating by pushing the pedal down it stalls/backfires until you let off the pedal like the carb is being starved. Could you have an open float flooding it? I am by far NOT a carb expert. I can't wait to get this carter junk off and put the MC 2100 on and eliminate all the vacumm lines.

1984 CJ7 w/ AMC 258 i6 / 4.2l

 

[Greg]

It sounds like you might have a carb base plate gasket leaking,or intake manifold gasket leaking,when the moter gets warmed up the metal expands and allows an air leak, you might try spraying some carb cleaner around the base of the carb,and around the intake,after the motor is warmed up,if the gasket is leaking the motor will idel up.

 

[JR74CJ5]

I guess my situation is a little different, its not so much coming to a stop, its taking off from a stop. So say I'm at a stop sign, start letting the clutch out and start giving it some gas, the engine starts to pop, spit and sputter a little unless I over rev it but then just after I let the clutch all the way out it will backfire. This is only the case when it gets warmed up though. Also, say I'm driving down a straight road going 25 30 mph, you can hear it spitting a little, it goes away a little when I get moving a little faster. So I dont know if it would still be a vacuum leak or what you said, "broken linkage". Could you maybe elaborate a little on what you mean. should I look for just anything broken or am I looking for something specific that could be doing this.

Just to give you a little more info, my carb has every vacuum cut and plugged, or atleast I think all are plugged. When I get home today I can take a pic of it and post it if that might help.

Thanks guys. I kind of feel like I'm back in college taking a class in "How to fix and trouble shoot your Jeep"!!! Haha, thanks again.

The broken linkage i referred to was a small bar going to a "plunger" type diaphragm on the top of the carb. This bar would allow the diaphragm to open or close the butterfly at certain points while driving, I am not really sure the technical name of the part or if you even have something similar.

Pretty much the only thing i can thing of is to look over everything real good, and if you see something that looks "off" post a pic...

This could possibly be a few other problems all together though... Like timing, carb mixture is slightly off, I'd suggest auto choke adjustment but i think i remember you saying you had a manual choke... It's just hard to know without being there you know...

I have even noticed my motor running crappy at certain points due to exhaust header leaks...

Grab a case of brews and start looking everything over you know...



~ JR

 

[musciab]

Got the beer, and will head out today to grab come carb cleaner to check for leaks around the base of the carb and the intake manafold. I will also check on that bar thing you guys were talking about as well. If I notice something that dosnt look right, I'll get a pic or two and post it. My buddy has a webber 2bbl that he is thinking of letting go, so I might look into that as well just to get rid of this mess I have now. Thanks for all of the help. I'll let you know what I come up with.

 

[Old Dog]

Just to give you a little more info, my carb has every vacuum cut and plugged, or atleast I think all are plugged. When I get home today I can take a pic of it and post it if that might help.

Thanks guys. I kind of feel like I'm back in college taking a class in "How to fix and trouble shoot your Jeep"!!! Haha, thanks again.

You need a vac. hose to the distributor for the vac. advance to work.
I would also check that the acelerator pump was working while your looking around.

 

[musciab]

Does anyone have a good, easy to read/labled diagram for the vacuum lines???

 

[dunebuggy18]

I agree, it sounds like a vacuum issue. No other performance problems? Any valve rattle when pushed up hill? If carb cleaner does not identify a vacuum leak, go back to the basics: check timing and pull the plugs one at a time to be sure that they are burning clean. (I'm bettin' on the vac leak!)

 

[kencc56]

Check out this link. It has all kinds of good info about vacuum, etc. Table of Contents

 

[dunebuggy18]

If you are still lookin' for info, check ou this link: Vacuum Line Routing

Several diagrams for the EGR, canister, fuel and PCV valve are shown.

 

[1986cj7]

Mine kinda does the opposite. It idles fine but when under a load or accelerating by pushing the pedal down it stalls/backfires until you let off the pedal like the carb is being starved. Could you have an open float flooding it? I am by far NOT a carb expert. I can't wait to get this carter junk off and put the MC 2100 on and eliminate all the vacumm lines.

1984 CJ7 w/ AMC 258 i6 / 4.2l

I dont know why everybody is down on the carter carbs, yes the vaccum lines are a pain in the a** but if changed out to new lines one by one as not to get them mixed up the carter in my opinion is a good carb. Now also the smog patrol is also a problem but I'm lucky in missiour they dont sniff test the exhaust. And the po took off most of the emission junk. But my carter run great, the only thing I need to work on is the electric choke. The first time the spring was disconected from the cover plate, now I'm looking for a new electric choke, so that may be a problem. And I may have to replace the whole carb but I think I'll go with another carter if possible. Depending on price and all. Just my opinion.