Don't know for sure, but Kioritz and Echo are pretty high dollar engines, I don't think McCulloch would buy from them to make weedeaters..McCullochs were made here in Lake Havasu City, Arizona before they went bankrupt...Harbor Freight bought some of the finished ones and 2 guys here in Flagstaff but tractor trailer loads of unfinished stuff....I think the name went to China, like SuperTigre.....
A Koritz should have the Echo symbol, a stylized "E" somewhere on the case or cylinder...Looks like 3 small Christmas trees on their sides to form the "E"...