Welcome to the forums. It could be a firing problem, but it sounds a lot like a carb problem, too. The idle circuit might be about stopped up.
If it's a firing problem, it sounds more like it could be the ignition coil getting hot. Usually the stator is just the opposite when they go bad. Usually they don't want to start when they are cold and you have to push them off, but when they get warm, they start alright.
If it's a firing problem, it sounds more like it could be the ignition coil getting hot. Usually the stator is just the opposite when they go bad. Usually they don't want to start when they are cold and you have to push them off, but when they get warm, they start alright.