Thanks Joe, that is great.
I will hone it and put up an image of the results.
Yes, I think that the block held up well considering the shape of the piston.
The back story on this engine is, the previous owner got the mower from his dad in Rockhampton. They had the machine for 25 years.
I have seen a newer one of these with the piston looking much the same, the bore didnt hold up aswell. Had more scoring.
I havnt played with a key start yet. So the one with the plastic piece is the later type? To accomodate the starter, and the flywheel has teeth, I think I get it now.
Cheers