I picked up one of them with it, just been out and had a closer look at them, and my old Ryobi I am working on, the McCulloch has the carby to the side, these two engines and my Ryobi have it in-line with the shaft, don't know if that means anything though. it certainly has similarity's top the McCulloch.
The spare has a no carby, the one without the labels has a walbro WA62 , and the McCulloch has a WA146.
I took a few photo's, should b e able to get them up here tomorrow.