[Excaliber]

Had that happen to me once. I got the car started by cranking the starter with the trans in gear. It lurched and bucked and finally fired up and away I went (like your go kart thing). I then NAILED it HARD! I was surprised how hard and how long I had to hold throttle on it before the clutch finally freed itself. Worked like a champ after that!

I think your onto something with the 'go kart' thing, just didn't 'nail it' hard enough/long enough to break her loose yet.