View Full Version : Jeep stalling question
08-02-2008, 09:28 PM
Okay, this isn't quite an expedition question, but I am hoping others have encountered and resolved this issue, and can help me do the same.
I have a a POS 1971 Jeepster that I like to crash around in. It does all right, until I get into the steep stuff, and then it has a stalling problem. Almost like clockwork, when the trail is steep enough to lose traction on all four corners, the thing stalls and scares the heck out of the co-pilot.
My brother just brought home a 1984 CJ-7 yesterday. It does the same dang thing under the same conditions! Point the nose skyward, and it stalls. (Incidently, his has the additional trait of stalling when you point it steeply downhill, too.)
What is the deal with this, are Jeeps level-ground only?
Any info or interesting guesses greatly appreciated.
Thank you, Esmi
Carb float level set to high. :beer: :beer:
08-02-2008, 10:04 PM
My first thought was also float level.
08-02-2008, 11:58 PM
ditto...and if you guys dont want the POS CJ-7 let me know, I know how to make it run right
08-03-2008, 12:57 AM
Wow. Thank you for the fast and consistent replies!
Second question: Do you usually adjust your float with the little dinky hammer or the larger one?
Let me rephrase that a little: Is a float adjustment something that the internet can teach me how to do in part of an afternoon; or does one typically remove the carb and send it in for a complete rebuild?
08-03-2008, 01:24 AM
Actually, I believe you will find that the float level is not the culprit, although it could be set too high. The stock carburetor on that generation of Jeep was not off-road friendly, and there is just about literally nothing you can do to remedy the problem. Tilt the vehicle too much (usually more than 20 degrees) and fuel spills from the float bowl into the venturi stalling the engine. The same happens if you hit sharp bumps, such as climbing a creek bank or such.
I replaced my carb with the typical aftermarket one for Jeeps and largely remedied the stalling, but also sent the fuel consumption from 20mpg to 10mpg with no appreciable increase in available power. I was never happy with that particular replacement carb.
Still, swapping out the carburetor is the only way to overcome the problem in my experience. There are several options as I recall, with a used Ford one barrel carb being one of the best and cheapest. For the Jeepster, try posting on the Early CJ-5 web board. They have lots of tech experience in this area and lots of Jeepster guys who can perhaps give you a better idea on how to fix the issue.
08-04-2008, 04:47 PM
Is a float adjustment something that the internet can teach me how to do in part of an afternoon; or does one typically remove the carb and send it in for a complete rebuild?
Since we all seem to have overlooked this question, let me give it a try.
Adjusting float level requires removal and disassembly of the carburetor, or, if you are confident about taking carbs apart and not dropping tiny screws down the throttle bore, you should be able to make the adjustment with the carb still mounted by removing the top of the carb from the base while it is still installed. This exposes the float bowl from the top and allows the float to be removed.
Adjusting the float requires VERY SMALL changes in the bend angle of the drop limiter tab. You want the float to seat the float needle while it is closer to the bottom of the bowl rather than toward the top. Too much adjustment in this area will leave you starving for gas under acceleration or other fuel starvation issues due to too little fuel in the bowl. Float arm should be about dead level to the horizon when correctly adjusted, so just a couple of degrees below horizontal should be sufficient to drop the bowl level enough for you to see an improvement in the ability to do off-angle trails. While you have the carb apart this far, verify that the float needle is perfect. If it is not, replace it now. If you are lucky, you can do all this without having to replace gaskets. If you tear up the bowl gasket, get a new one. It will work with a torn gasket, but will probably leak gas which can be bad on the trail.
The real problem you face, however, is that the stock carbs are not designed to suffer steep angles. They intentionally overflow fuel from the bowl to the intake when tilted more than about 20 degrees. You could experiment with raising the overflow inlet height, but such modifications require a degree of design and fabrication skill that is beyond written discussion. If it were easy to do, lots of folks would have done it over the last 35 years of living with Jeep carburetors. That they are not easy to remedy is the reason there are so many aftermarket carburetors still available today. One replacement "off road" carburetor even has a raised vent tube which puts the vent so high that it would literally have to be upside down to leak. If you can find a way to modify your carb to put the overflow vent higher by even a quarter inch, you will increase the roll angle you can sustain by a significant margin.
Add to the situation with the older carbs the probability that if your carburetor is the original, the throttle plate rod is almost certainly worn out and leaking, which causes air leaks that drive the idle speed around uncontrollably (rough idle). Most older Jeeps have trouble controlling idle speed, and often the problem is attributable to this issue, caused by time, dirt, and wear. Another issue that can not readily be repaired. The throttle body needs to be bushed and the rod replaced, or a rebuilt carb needs to be installed to fix a leaking throttle plate rod.
If you have the time and money, fuel injection is the best option. Otherwise, I would look for a replacement style carburetor if you intend to take the older Jeeps off road regularly. The stock carb will simply drive you crazy on the trail. Most of the Jeep catalogs have replacement carbs available and the prices are fairly consistent from source to source. If you do this, don't go crazy with larger models or expect performance increases. Marketing blurbs all refer to increases power and better economy. Reality is that they do function better off road, but deliver economy no better than stock, and usually worse than stock unless you are very good at rejetting carburetors. For general off road work, a smaller bore carburetor will give you better economy, better torque, better throttle response, and will be easier to adjust to your engine. since we usually don't drive WOT on the trail, big bore carbs don't do any good off road.
08-04-2008, 05:05 PM
I have a 1971 Jeepster .... and a 1984 CJ-7 .... that stall in the steep stuff. What is the deal with this, are Jeeps level-ground only?
For what it is worth, Jeeps have been manufactured by several different companies over the years, each having a different philosophy about the purpose of the product and its intended market. Early makers such as Willys and Kaiser built Jeeps for rough use as a utility farm tool or off road vehicle. Originally they did not even come with tops, much less radios.
Back in about 1971 or 1972, Jeep was sold by Kaiser Jeep Corp to American Motors. While AMC made a lot of good changes to the marque, they aimed at a far different market than earlier builders because they wanted to sell a lot of Jeeps, not just a few. In few words, Jeeps became far less off road capable under AMC. That trend toward street use had not changed since the early 70's. That they could still be used successfully off road then and now is not the argument. Jeeps have not been built specifically for off road use since the late 60's.
So perhaps it is fair to say that they really were built for flat trail use. But then, that's why the after market for Jeeps has increased as it has. Back in the 60's, you could not find very much available for modifying Jeeps. They didn't really need it, not many were interested in doing it, and those who did modify Jeeps were fabricators and experimenters many of whose names now adorn after market products.
08-04-2008, 08:41 PM
The Carter carb used on your era Jeep will cause you headaches no matter what you try to do to "fix" it. Aftermarket Webbers are a good fix, but you will never pass a smog inspection again.
The only sure, smog legal, fix is to convert to a CARB approved fuel injection system. Hesco makes the best (based on Mopar parts), but it is not cheap. Howell makes another, cheaper but more difficult to tune properly.
Jeeps R Us in Laguna Beach CA [(949) 497-9183] used to have a line on a supplier for rebuilt Carter carbs that seem to work better than the rebuilds typically available. You will have to ask, but my recollection is that they are built to specs provided by Jeeps R Us based upon years of experience with crappy Carter carbs. I used one for awhile, together with a Cagle fuel regulator (now impossible to find), and had few problems in the steep stuff.
Then I injected my CJ. Best thing I ever did to that motor.
08-14-2008, 01:00 AM
A tardy thank you for all that information!
In the intervening week, my brother found that the PO of his new-to-him CJ-7 had leaned the carb waaaaay out to help it pass smog (in order to complete the sale). He and a smart friend have re-adjusted the carb back to right, and he assures me it stalls less in the steep. I have not independently confirmed this.
About the Jeepster with the Dauntless: I haven't done nutin' with or about it for several days. Being a long-overhang, low-clearance, non-posi P.O.S., I don't think I am going to afford to change the carb for increased trail performance.
What is likely to happen is that I will take the top cover off, adjust the float to where it doesn't run at all anymore, lose a couple of smallish parts, THEN go buy an aftermarket setup.
Thank you again for all the help.
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