Sometimes it will - sometimes it won't !

Sometimes it will - sometimes it won\'t !

I finally got the 'Pony' carb idleing pretty good and got it to shut off (most of the time ) when I turned the key instead of having to pop the clutch in gear - Actually it was running pretty good. It sat over night at work - started it in the morning and warmed it up before I hit the road thinking that would help with the carb icing I always get !! But NOOOOO - the thing would not idle at all - running ruff and blowing blue smoke at the stop light !!!!???? I had to stop for the carb ice - that cleared up like usual but still would not idle at all. Thats when I niticed the light blue smoke that was not there before. I had to baby it home using the parking brake at the stops. Now this afternoon it is running fine again ?????????? What the *&^% ?????
I tried all of what I have read from you guy's - also going back and reading the seach pages.
Could it still be dirt in that carb ????????