I just bought a plane with a evolution 61 I think it is the nt motor runs great looks like it has very little use on it the problem i have whicth isnt very big when i idle it down it wont die even with the barrel completely closed you can see the grove in the carb barrel where the idle stop screw rides i think it is just sucking to much air to die but it is a very low idle and after a min or 2 it will finaly die i just would like it to die quicker any opinions would be appricated

Try loosening the two screws that hold the carb - Don't remove them, just loosen. Then push down on the carb and while you're holding it down, tighten the screws. If it is sucking air past the O-Ring, that should cure it.