Help With Rochester 2bbl Carb

So I finally got my 1969 CJ5 running but I am in need of some help with my carb and keeping the Jeep at idle.

If I keep the choke closed (butterfly closed/choke cable pulled out) it runs fine. As soon as I release the choke and open the butterfly the engine dies. It doesn’t matter how long I let the engine run and warm up, it still dies as soon as the butterfly opens (push the choke cable in).

The Carb was rebuilt about a year ago but never used until a week ago.

Anyone know what I need to do or need to look at to solve my problem? It is a Dauntless 225 OddFire with a Rochester 2BBl carb (manual choke). I am guessing I need to adjust the idle but I don’t want to screw this up. Any help would be greatly appreciated!

 

If it only runs with the choke closed, you have to have a massive vacuum leak.

 

Would that be a leak from the carb to the distributor or is there somewhere else I need to check.

If I understand correctly there are only 2 vacuum locations on the carb, one for the PCV and one to the distributor. Is there someplace else I need to look?

Could it also be an ignition timing issue? Just trying to figure out where I need to put my attention. Thanks

 

What should the RPM’s be with the choke closed?

 

You could also have a leak at the base gasket or the vacuum ports on the intake manifold. When the carb was rebuilt were all the settings reset to the recommended starting settings? The mixture screws were set way too rich when my G2 was rebuilt and ran like crap untill i readjusted the screws.

 

What should the recommended settings on the carb be? I can check that pretty easy.

 

Might be a really dumb question but if the only two vacuum lines I have are the line on the back of the carb running to the PCV valve and then the other vacuum line running to the distributor and any other holes in the intake manifold that could have been for vacuum for things like heater core, wipers, etc have all been plugged am I missing something?

I'll check the FSM as well for info.

 

I’d recommend following these adjustment instructions to see if that fixes the problem
https://www.carburetor-parts.com/assets/instructionsheets/K427.pdf

 

My 70 (made late 69) smog compliant Dauntless has a vacuum port center and aft on the intake manifold. I have heard it's rare, and not necessarily the desired rare. Take off the air cleaner and poke your head back there center aft and see what you got.

 

If you need pictures give me a day or two.

 

Pictures would be great. Thanks for the help!

 

Specs should be in fsm or rebuild kit instructions. Unfortunately I dont have either handy at the moment.

 

Considering that you just recently installed the carburetor you likely used a new base gasket, but just be aware that the gasket is known for deteriorating from exhaust gases that run under a portion of the carb base.
If you used an old gasket check it for integrity.

 

spray carb cleaner around the outside of the carb base to check for leaks. that may help point you in a starting direction.

 

Ok so I was able to work a little on the carb today to investigate a few things. First thing is first, I have both the PCV Vacuum and Vacuum to the distributor hooked up and sealed. I started the engine with the choke closed and it fired right up. I sprayed some starter fluid around the gasket area where it is mated with the intake manifold and didn't get any increase in RPM or any indication that there was a leak anywhere. I open the choke and the engine immediately dies (1-2 seconds).

When the choke is closed it is running at about 600 RPM if that matters for this.

Below are photos of the carb, anyone see anything that is horribly wrong (minus the temporary spring and dashpot needing to be replaced)? Looking for things that would cause the engine to die once the choke is opened.

 

“When the choke is closed it is running at about 600 RPM if that matters for this.”

that’s likely your problem. With the choke closed, your idle should be significantly higher than 600. There is a cam that the idle screw rides on. As the choke is opened, the cam turns and the idle decreases. If you start at 600 choked RPM, your unchoked RPM is probably close to zero and the engine will die.

I’d increase the choked idle to about 1,500 and then once the engine is warm you should be able to open the choke and it will still run, but at a lower RPM. Then set your idle to factory specs (750 if I recall correctly) and you should be good to go.

 

Something looks weird on the drivers side of the carb. The linkage should look like this picture and you can see the idle screw on the cam mentioned above:

 

His carb is missing the throttle relocation bracket, so the rod is attached to the wrong ball stud. The idle screw is there, but hard to see as it’s partially blocked from view. This also causes the gas pedal to sit to high.