Stalling

So I rebuilt the carb. Learned that their is no power cable in my 2CG. But I don't drive it fast anyways. Question is....when I come to a stop the jeep stalls. If I glass it before it quits it's fine. I'm at a loss. Only vacuum is the advance. No power brakes. It's on a 225 dauntless. Any suggestions would be great. Thanks!

 

no power valve it kit . but 2G does have one . I suspect float not set or should be replaced
http://www.carburetor-parts.com/Rochester-Power-Valve_p_885.html

 

Brand new float. I would replace the power valve but I don't have the plunger and the PO welded tho hole. Run fine without it. Only issue is stalling when braking. So which way should I adjust the float. Higher or lower?

 

Do these carbs have a dashpot?

 

Nope. Mine doesn't!

 

If the carburetor has a power valve, the engine will not run right without it. Its purpose it to enrich the mixture when you open the throttle at low speed, to prevent a lean mixture at low vacuum. You need it, or something like it. Different carburetors implement this requirement in different ways. The only way you can do without it is to run very rich all the time, so that opening the throttle does not make the mixture too lean.

"Welded up the power valve" is a big red flag. What do you mean?

Typically the TSM has a very good description of the carburetor circuits and principle of operation. I would start there, by studying the section and understanding what is there.

Usually, when an engine stalls as you close off the throttle, it's too lean. Vacuum leaks can cause that, or too-lean idle mixture.

 

So as Tim said "it's purpose is to enrich the mixture". The power valve pin in the up position is closing off any fuel flow and without the power piston (you say is removed and plugged) the carb has no control of fuel flow and cannot differentiate between idle and full throttle. Be sure you understand what goes on in the venturi circuit about the carbs reaction between venturi VELOCITY and venturi VACUUM. Once you get a clear picture of this then you will understand why it dies at decelleration.

 

My 1971 cj Rochester 2G requires a dashpot. The original was worn out, and when I tried running it without it, unless I had the idle set real high it would stall when I came to a stop. I was able to find a new dashpot at quadrajetparts.com, part number Q4410A. However, they no longer show that part on their web site. This one at carburetor-parts.com appears similar, but I'm not sure that it is the same:

https://www.carburetor-parts.com/Dashpot-Assembly_p_2916.html

 

Now that you say it my carb has a dash pot. It's how I adjust the idle!

 

The dash pot is supposed to provide a gradual transition to idle, when the throttle is shut suddenly.

Specifically, to prevent stalling exactly such as you describe... If you have bottomed it out to hold the idle, or it has failed, the dashpot may not be performing it's function.

The idle stop screw should be used to set the idle (duh), and the dashpot adjusted to softly absorb the last few degrees of throttle rotation at shutdown.

 

Yeah. Must be missing something. My idle set screw touches nothing. So no adjustment.

 

You screw the dash pot away from the throttle until the idle screw seats on the cam. You set this screw for proper idle speed then screw the dash-pot until it touches the throttle. I then screw the pot one turn in and work the throttle. I can watch the pot slowly collapse until the idle screw has reached the cam. If the engine still dies on de-celleration I move the pot another turn. Eventually you will find the sweet spot.

 

Thanks man. That seems to make sense. Do you happen to have or can you take a pic for me. If not its cool!

 

Well....my dash pot is solid with no movement! Ordered a new one from Mikes Carb. I'll report back when it's in. Thanks!

 

If you have not replaced the top of the carb with a proper working one with the vacuum piston, your carb will still be a problem. Re post #6 as Tim states, the engine needs rich and lean variations depending upon the demands. Without the piston there is no control of the power valve. The accelerator pump gives the engine that initial squirt of fuel it needs to rev and then the power valve takes over in a smooth transition.

 

The dash pot is also an emission device. Prevents flooding of the engine when the throttle is closed quickly and helps to reduce excess unburnt fuel.

 

seeing its still apart on work bench
as/was top crud and rust on inside power piston junk

new piston

new power valve

 

I found a new power piston and power valve at mikes carb. Pretty cheap so I ordered it today. Should be easy to install. I'll just leave the carb on and pull the cover. Install them both and hopefully between that and a new dashpot my stalling issue should be gone. Maybe now it will also fix the quarter choke issue and be able to run it with no choke on.