It looks like a Weed Eater Weed Whacker with the reverse fins on the flywheel?

The 33cc Weed Eater does have a double ended crankshaft and might lead someone to think it came from a small chainsaw.

The 33cc chainsaw engine is a clamshell design with the cylinder and the top half of the crankcase as one piece. There are fins all the way up and down this thing and it has a slanted spark plug.