My friends blasty did this. Revved to the moon with the ket off, spark plug unhooked. Pulled the choke and killed it. Turned out the crank seals were the culprit.
dude thats bull sh*t it wouldnt keep running if u pulled the spark plug there would be no spark to lite the gas and keep it running
Once it gets to a certain temprature it runs off compression + heat. Turns into a disel, no need for spark plug.
edit: sorry forgot to mention, this doesnt always happen. i should have said it does this when it goes lean, ie: air leak.
check intake and other seals including the base gasket and crank seals.
OH relly!! wow professor 89 to teach me thanks!!
forgot to mention 2 strokes only. actualy, dont quote me on that, ive just never heard of a 4 stroke do it.