I had a similar problem from a Craftsman model 663 two stroke engine
from the late seventies. I tried to look up your model but could only
determine that it may be from the same time period.

I fixed my random shut down for no apparent reason problem by
disassembling the bottom of the carburetor and cleaning all the
accumulated gunk out of the bowl. Be careful of the paper thin rubber
gasket. I was able to do this without buying any new parts. It's still
working today at an age of about 26 years.