My 70 340 is built stock and was running good. It has less than 200 miles on it since restoring my car.

during previous drives, I noticed a stumble/hesitation on accelerating after releasing the throttle at cruise and re-applying gas. Figured I'd fix the car later as it was not that big a deal.

Yesterday I had a friend out in it and it began to stumble repeatedly. I could not tell if it was a fuel or ignition thing. The carb has never been very sensitive to idle adjustments (factory AVS). It would stumble when driving and while idling... almost as if trying to cut out and then kicking back in.

Took the AVS off and found a bad float. I replaced that and reset the floats. When I went to start it it would not run at all. It would run, then suck air and try to die... kick back in and then do the same thing.. laboring to run but trying to die. I could not keep it running much less idling. I took the AVS apart again... cleaned it again, made sure the floats were adjusted right put it back on with the same results.

I changed the coil... no change. I pulled the distributor and checked the points gap that was OK. It seems like carburetion since it is the only thing I handled. I have rebuilt a lot of AVS's and have worked on so many engines but have never had a motor run like this - especially all of a sudden.

Any ideas sure would be appreciated.

Thanks

I would shoot a 2 second blast of starting fluid into the (2) idle mixture screw holes (need the thin red straw to do a good job on this) & if that ain't it then I'd open the carb up again paying attention to gasket condition (vac leaks) & I'm assuming you have a good AP squirt (& immediate tip in) when the throttle barely moves. Holler how it turns out

whats your timing set at? initial and total

It was running and idling prior to taking the carb off - with the miss/stumble I previously mentioned.

When the AVS was apart, I sprayed the idle holes with carb cleaner and witnessed a nice blast through them. Cleaned all ports and emulsifier tubes. I had pulled the distributor to check the point gap and re-installed it. It had to be a few degrees off but not enough to cause it to run like this.

It runs than dies out... kicks back in and then dies out again. I can't keep it running at idle or past the idle circuit which is strange for an AVS. Checked vac leaks etc. That isn't it. It almost seems as though I am intermittently losing ignition.

Do you have or can borrow a good carb to see if that's the issue? The junk gas we have today is tough on carbs.

Ya, I have a another AVS I am going to try. Also will look deeper into the distributor... It acts like it it loses its spark intermittently. Could a bad condensor cause that?

It ran ok, but had a stumble. You took the carb off and now it won't run. Unless you broke something else while in there, the carb IS your problem...

Yes, logic and common sense would point to the carb since the car ran prior to removing carb and going through it. After getting the carb fixed and put back on the car and experiencing the same thing, I walked away.

Yesterday I was reading about the affect that a bad condensor would have on a car. I found a thread that described the exact sypmtoms I was having that was fixed by replacing the condensor.

I know AVS's well and knew it could not be making the car run as bad as it was. I went and got a new condensor and points, removed the distributor set it up with those pieces, re-installed it and it ran great. No sign of previous stumble/miss.

Thanks to all for your comments!