I have an older engine that came off of a Mac eager beaver weedie.It is a echo 16cc.dont throw that engine away first of all.Also look for 3 elongated triangles shaped like a christmas tree,but there laying on there side so it looks like the shape of an [E].Check around cylinder base and around rear crank housing.That means echo brand.Also i did the math like this:
1.2 inch=about 30mm-just an estimate.
15[2]x3.14[pie]=706.5
706.5x30mm[1.2inch]stroke=21,195
this means the cc is about 21.1-21.2.
I have 2- 22cc echos [21.2-4 actual] on 2 of my hedge trimmers.One of them matches your exhaust bolts,staggered.If ya go to echo-usa.com and put HC-200 in the search bar and then click on the manuals,parts pics ect,see if those match your engine.I think they will.I think its an echo 22cc and is very eligible for a conversion.Im doing one right now.