What is happening when it shuts off? I would imagine you are getting too much fuel, and/or not enough air so it loads up and stalls. If you are giving it air while it dies it could be the opposite. I've not changed the air mixture on mine yet but I can tell it's getting too much fuel through it. I've kept it like that so the components stay well lubricated while they seat. When you say "tune" I suspect you are talking about the air/fuel mixture? Also check the glow plug coil is still burning hot when you remove the ignitor. That's all I can really think of that would cause this. Probably not much help, but it's what I would rule out. Let the forum know what it was once fixed please.