i am also haveing the same problems mine starts some times then it dies right after and it spits out feul outta the muffler so i leaned out the high speed needle and it still does the same thing i don't get it i might need to change the glow plug because it is old but it still lights up when put on the glow plug ignighter but i don't even know the break in settings for my model
it is a kyoshovanning land jump with an os max .21 on it