I realize that this is not helpful, but I had  the same problem a couple years ago. I don't have it now and I regret to say that I don't know what fixed it. Perhaps my mental librarian will pull up the memory. 

Sent from my 1963 aqua blue 702B Western Electric Princess phone. 

On Aug 5, 2013, at 11:14 AM, Bryan Feddish <uprightbassghost@HOTMAIL.COM> wrote:

>>> Tell us in detail about the symptoms? <<
> 
> After the engine warms up the idle just goes up and down about every second.
> If I'm missing some helpful details let me know.
> 
> 
> Thanks,
> Bryan