ORIGINAL: TimBle
Beginners crash. Crashes break airframes and damage motors. So are spares available for K&B .40 size 2strokes?
Whether money is an issue or not: Why should he buy an engine when he already has one?
It really does not matter if spare parts are available for the old K&B.
I'd use it until it breaks or wears out. Then I'd contact
http://www.kbmfg.com and ask about parts. If it made sense, I'd rebuild or repair. If not, I'd buy a new engine at that time.