I have no knowledge of what this is, whether it be for a strimmer or other tool or even a model aircraft engine  I know that this lump weighs 2.35 Kg so probably for a tool.

Maybe Komatsu Zenoah as it came in a box with other Zenoah parts which I will listing today ...

Am starting at £10 as it may be worth this in parts to repair another engine.

It does seem to have some sort of clutch type mechanism at one end -see photo

It also has the following numbers that i can find on it   - 43 on the cylinder head   and also 302- AIPU