Hi Dave!
Your right! It is a Kioritz. The ones with the squared clyinder like yours are the largest cc-wise and may be as big as 25cc. More likely over 22 anyway. I have never measured them. They seem to be well built little engines but there is quite a lot of differences in port sizes and bearing types between outwardly similar engines. Also not all are solid state ignition. They were used by several brands but most often are McCullochs...........farley9n