Hi!
I'm new to the forum, so please forgive me if I screw something up in the posting process...!
In short, I've got no idea (sorry!), but I had exactly the same thing happen to me on my carbed '83 Brumby (Brat) after some drunk moron ran into the back of me a few months ago. She stalled soon after the collision, and upon restarting her, ran like a dog until I gave her full throttle for a period - then - no problem. I've never seen the problem since... weird.
Cheers,
James :-)