Does anyone know what size the recessed central nut holding the
flywheel fan casting on the engine of one of these beasties is? I
bought one (non running) for entertainment and repair and need to
strip it but can't find anything in my tools to fit it. I am guessing
it will be either BSW or imperial AF but with a thin wall socket as
there isn't much clearance. Secondly is it left or right hand thread?

John