Thanks BB.
Is the earlier clutch body the one with cotter pin that doesn't go through both sides?
The single mower's clutch body has a cotter pin that goes right through and the twin rail's doesn't - so now I am a little confused?

What would be the diameter of a b+s crank be on this later motor? Just want to make sure trhe clutch is the right one before I throw it away!

Thanks for the lesson on keys ad all your time and help!

Cheers

Mark