Well, my motorbike's carbs did the exact same thing. I would have rubber, and cork gaskets fail. So I cleaned the bowl out, and used a fine sand paper to make sure that all gasket material was removed. Check your float level, it is probably out of wack. There should be a needle atached to the float, make sure that it moves freely and doesn't stick. Then you could use a liquid gasket (mine was for offroad motorcycles and snowmobiles.) It should be a high temp, oil and gas resistant, and non-hardening. Try to get one for high-performance engines, it will last longer.
I swear by gasket makers, I have used them on carbs, oil pans, valve covers, ect. I am amased that the little $10.00 tube can do so much! Saved me from having to walk to work alot. Great temp fix.
