CJ7 idle again

Wild guesses:

Way too rich at idle. Dirt in the needle and seat? Needle and seat leaking? Gas level too high in bowl? Idle adjust screw(s) way out of whack?

-- Dale Beckett

I'm guessing, but based on your information, I'd say this, first, it's running well while the choke is on, but not after the choke plate is fully open. This would indicate to me a very lean condition, possibly a leak of vacuum, intake leak, carb base gasket leak, pvc valve or system leak, or, mal-adjusted carb.

It needs to be more rich than it is. This is what happens when the choke is on, less air, more fuel, and it runs fine. Once the choke opens and the mixture leans, it runs rough. You can check by spraying small amounts of flammables around these areas to see if it smoothes out. My favorite trick is to use a gas cylinder and valve from a torch with a hose on the end and lightly turn on the gas, if your motor smoothes out, you've found the leak.

Spdloader

I was thinking just the opposite, based on what he said about flooring it to start warm. but you could be right if the choke is working.

-- Dale Beckett

On Thu, 22 May 2008 22:39:26 -0400 in rec.autos.makers.jeep+willys, "Spdloader" wrote,

Yes, I leaning more towards the too lean guess than the too rich guess. I will do the carb spray check for vacuum leaks routine next opportunity.

How can I quickly tell the difference between grossly too rich and too lean?

I should have mentioned, it had been running fine for a long time then this came on quite suddenly, so I suspect something failed rather than any misadjustment.

The carb base bolts can come loose or the intake manifold can be loose and then blow out a chunk of gasket even causing it to suddenly jump bad. Or it was just a slow loosening that went critical.

I would carefully spray some carb cleaner or WD40 along the intake manifold gasket and carb base looking for an engine stumble.

When you shut it down, do you get any gas leaking around the carb?

A blown float needle seat can sure cause your symptoms too. I have to physically clean my needle and seat every couple years or replace them.

Sometimes you can actually see the gas being poured down the carb throat when this happens as it is running.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:

The best fix for these things is a carb kit and make all the adjustments as you reassemble.

And

- don't reuse the old carb gasket.

- use a steel to determine if the carb base and intake is level

Sometimes when folks put carbs back on (or when they find a small leak) they solve that by overtorquing the bolts. This bends the ears and creates even more leaks. A bit of sandpaper on a flat surface can be used to work the base down a bit. The other thing is watch the gasket, some have a front and a top.

On Thu, 22 May 2008 15:27:23 -0700 in rec.autos.makers.jeep+willys, David Harmon wrote,

Thanks, everyone, for your thoughts and suggestions. I'm afraid I got busy for a while and so I didn't do much more troubleshooting yet. I've just been driving it. And, who could have guessed, it's gotten better in the mean time. Almost back to normal, even.

Which leans me toward perhaps believing in the dirty float valve idea. I dunno, maybe some dirt somewhere washed its way on out of the system.

I still need to clean up the carb. In fact, what I'd like to do is get a junkyard carb and rebuild it, so I could just swap them and have a spare.