I rebuilt the stock 2150 carb on my 351m two weeks ago and it ran fine, but only for a week. Last week I started having a problem with the idle. lopey idle, sometimes it dies. Don't know where the problem could be. I have opened up the trottle at idle to keep it from dying, but i would rather fix it. The choke is wired open, so I know that is not contributing to the problem. I adjusted the two idle screws and nothing seemed to change.

Any suggestions?

 

what your describin' sound like the power valve. run your idle screws completely in (seated) if your 351 still runs (however rough) the your power valve is bad, and needs to be replaced.

 

The power valve was replaced with the rebuild, little thing on the bottom of the carb, right?

I ran the idle screws in all the way and the engine dies. worked the screws out from there and about 2 1/2 turns it seems to be running better. I also had a small leak sound as well and added a gasket between the EGR plate and the carb and the sound is gone - and idle is better, still a little lopey.