Just had something similar happen to me, turned out that a piece of something had gotten under the main jet. Looked like some rubber sealant or Teflon. It would idle fine, then when I was about a mile down the road It would quit. As soon as it quit I think the obstruction would drop back down out of the way. Then it would start right up. I was already having problems getting the carb to quit leaking, so I stumbled on the cure accidentally.
That could very well be the problem. But I’m not putting anymore of my time into it. New carb going in tomorrow.
BTW what may look like a leaking carb quite possibly is the float out of adjustment. The float isn’t shutting the flow off before the gas level in the bowl reaches the gasket height. Or the float has a micro hole in it and is sinking. This would require a higher level of gas to shut it off.
Don
