Sounds as if you're getting "spark" enough to start and run a while, then sputters and dies. A weak coil could cause that problem after they heat up a bit. I wouldn't go into the flywheel, coil until I checked the carb first. I would check the kill switch and disconnect it and see if it runs ok. If it does the same thing, then I would clean the carburetor and diaphragm,clean fuel from tank, needle etc. A small amount of trash, water, crud in there will cause sputtering and dying. Carbs do not like water and foreign material. Hope this helps.
