F-134 inconsistent idle? help!

Hey everyone,

So I fired up my '57 CJ5 today for the first time in a few weeks. It ran great: I drove it around for about 15-20 mins. It sat for about 3 hours and I started it back up to drive around again.

It started up fine, only now when I let it sit at idle its not consistent--it idles, then drops to almost a stall, then picks back up to an idle again. I drove it around fine, but everytime I would come back to an idle, it would do the same thing again. Any ideas?

Would it be an idle adjustment on the carb (it has the stock YF), or would it possibly have something to do with the fuel pump?

It seems weird to me that just earlier today it was idleing like it was new, and now its doing this....

Thanks!
- Evan

 

Or piece of crap (debris) in carb's idle passages, try this once.. reveup the engine to around 2500 rpm's and listen to the tone of the engine then get out and pop the hood end remove the air cleaner, then rev up the engine to the tone you noted before and hold it there then put your hand on top of the carb to close off the airflow.. just before it stalls take away your hand. Doing this uses the engines vacuum to suck the crap out of the carb. Repeat as needed. It works great for a roadside fix or a diognostic tric to see whats going on.
If that smoothes out your idle then teardown CLEAN and rebuild your carb.

 

Hmm... Alright, never would've thought of that! I'll go try it right now!

Thanks again!
- Evan

 

Just a thought... if she decides to backfire when I have my hand over the intake, won't that blow my hand apart?

- Evan

 

Try doing an intake manifold vacuum check. "Hunting" can be caused by air leaks, bad valves, blocked muffler, etc. A vacuum guage is cheap and easy to use.

On my '57 I've had the entire muffler filled with acorns by those %$^ing squrrels.

But first I'd try adjusting the carb idle mix screw!

Good luck.

Pete

 

Nah. Might make it sooty and stinky, but won't hurt ya. Might ruin your shorts though. R)

 

I had a similar problem with my 66 CJ5 and constantly found it necessary to adjust the fuel mixture. It'd work for a while then start idling up and down again. Pulled the carb off couple time and cleaned it, reset the float. Nothing seemed to eliminate the issue.

About the same time I determined the coil was going out, the spark was breaking down once it was hot. I replaced the coil and condenser and have never had this inconsisten idle problem again. Could be coincidence.