downhill and stopping engine stumbles

Hi all, I have an issue with my cj. My engine will stumble on braking and also on downhill slopes(not as bad). I checked the idle tubes and they are not clogged at all. I watched to see if they dripped after cleaning and they do not. The jeep runs very well through the RPM range other than that. Does anyone think the float level may be the culprit? I tuned the engine today and it idles smoothly at around 950(it has a 78' engine), good vacuum, and about 7 degrees BTDC. Any help would be greatly appreciated.

 

What carb? 1bbl, 2bbl or 4bbl? Motorcraft, Holley, Rochester? Would help to know. I know the Holley 2bbls have this problem.

 

Its the typical carter bbd, and while I'm thinking of it, do you think it matters if I capped off the float bowl vent?

 

The Carter BBD was not available on a Jeep engine until 1977, and not on the CJ until a few years later.

A common problem with the BBD is stalling at idle. I presume you are familar with this problem since you refer to the idle tubes.

 

Thanks for the reply, I am familiar with the idle tube problem. My jeep has an engine out of a 78 pacer I believe, the engine code says 1978 and the only 2bbl was on a pacer that year. That's whats odd about this, do you think the float level could mimic this problem as well? I'd hate to take off the carb again just to check this, I adjusted it very carefully but there is always a chance I made a mistake.

 

It sounds like fuel is lulling to one side of the carb causing floats to cut fuel, or fuel to not reach the aspiration vent. UN-Blocking the vent might let your carb manage this. Similar prob happen with drag racing, only they are accelerating the other direction.