CJ-7 carb problems, please help.

[SenorCole86]

I have a 1980 CJ-7 with the I6 258 eninge and the stock double bbl carb. Every time I come to a stop now, it either idles HORRIBLY low and shaky with multiple backfires as I come down to idle speed, or it just gives up trying to keep running and dies. First thing I did when I got home was take out the whole venturi cluster and clean it out with some carb cleaner and a wire. Didn't help. I then replaced some of those vacuum hoses that weren't looking too good. I don't think that helped much either. When it is running shaky at idles speed, I can close the choke plate with my finger, and it runs fine again, leading me to believe something is wrong with the air/fuel regulator (don't know about that one on a carb engine) or the electric choke. There is also a lot of white smoke coming out of the tail pipe. I think this has something to do with oil getting in the combustion chamber but have no idea if it's related to the problem with the carb. If there was a crying emoticon, I would insert it here, but instead, I'm just gonna beg for help. Please help me guys, anything would be greatly appreciated. Thanks.

 

[Inspector-Gadget]

RE: Sorry to brag......

Hi-Ya, SenorCole86,

If your Jeep is generating billowing clouds of white smoke when the engine is at operating temp…bad news.

That thick white smoke is not smoke; it is steam. The steam is result of engine coolant leaking into a combustion chamber.

The usual suspects: cracked head, cracked block, bad head gasket.

Wispy white smoke generated at cold engine startup is no big deal. That sort of white smoke is exhaust system condensate, usually with water dripping from tailpipe. That white smoke and the tailpipe water drip stops as the exhaust system heats up.

Obviously, if you have a cracked head/block or bad head gasket, the engine will not run well.

A “leak down” test might be in order to help determine what is going on inside of your engine. Check also for the presence of a slimy brownish sludge on dipstick and/or engine oil fill cap.

A “leak down” test is “old school” diagnostics -- even older than me!. If you are unfamiliar with that engine test, let me know.

Sorry,

Gadget

PS: I hate to add what follows, but I checked your previous posts and discovered in your post of January 14, 2005 @ 6:56 PM that sometime in the past you poured water into the carb. The water being, for all practical purposes, incompressible could very well have caused the breakage of internal engine parts.

Pouring water into the carb of a running engine is, if I might coin a term, to cause a "dry-dock hydrolock."

Bad idea.

 

[SenorCole86]

RE: Need INFO quick

Hrmm, I'll have to check if the white smoke still shows up at operating temp. Thanks. But, ya, I'm not familiar with that test at all. It would be great if you could explin it to me or tell me where I can get it done if it's a bit too complicated.

 

[Inspector-Gadget]

clutch plates rusted together?

Hi again, SenorCole86,

RE: Cylinder leak-down test.

Rather than me typing out the theory and how-to of a leak-down test, thereby re-inventing the wheel, check out the following links:

http://www.jpmagazine.com/techarticles/73178/index4.html

http://www.morrowmarsh.ca/concours/techpages/leakdowntester.htm

http://www.650motorcycles.com/LeakDownTester.html

http://www.xs11.com/tips/misc/misc3.shtml

In the old days, a cylinder leak-down test was often performed after a compression test. If a mechanic found one or more bad cylinders with a compression tester, the next step was to determine what was wrong with the cylinder(s) without engine disassembly.

The compression test was the quick and the dirty test -- the stethescope. The leak-down test was the detailed confirmation -- the x-ray.

Regards,

Gadget

 

[SenorCole86]

RE: selling jeep in durham, north carolina

Alright, I'll check that out, thanks a lot Gadget. I'll keep you posted on the results.

 

[Inspector-Gadget]

You are welcome, Senor.

This is one of those times when I hope to be 100 percent wrong, and that the trouble turns out to be something much less serious.

Regards,

Gadget

 

[SenorCole86]

Ok, no white smoke when its at operating temp. THANK GOD. And I didn't think that could be it anyways cuz my coolant level has stayed pretty solid since the problem started. But I found another symptom of my problem. It runs fine for a little bit, then the problem starts back up again. It's kinda weird. It's real inconsistent. Well, I revved it up real high then went around and took a look at my tailpipe. It was making a "pop" noise and shooting bursts of flame from the tailpipe. Is this a symptom of backfire? I always thought backfire caused flame to shoot from your carb throat. Either way, I know this can't be good. Any help would be appreciated.

 

[derff96963]

RE: hard doors

I would say your probably need a new Carb. The carter BBD is not a bad carb when NEW. However once they get some age they don't work well at all. I would recomend either getting a profesionally rebult carter or get another Carb like A Motorcraft 2150. The Reason I don't suggest rebuilting the Carter yourself is in the case of the one I had. The major problem with it was it leaked air where the trottle plate rod went through. The rebuilt kit doesn't come with the bushings for there.

 

[SenorCole86]

RE: Re: Can

Ya, I was looking around for one of those motorcraft ones. I can't seem to find one on the motorcraft website though, cuz it only lets you search by vehicle. If anybody knows a place where I might be able to get even a used one for cheap, please post here. I'm gonna post in the wanted forum too. I was only going to buy a new carb if drilling out the idle tubes to .032" didn't work. But I can't seem to fin d .032" drill bit. But, any help on that motorcraft would be awesome. Thanks.