Thanks for the info guys. Unfortunately can’t soak in diesel as the fluid would run out past the impeller vanes. Have sprayed liberally with GT85, and will use my garden flame thrower to try heating it up.
However, does anyone know if it is LH or RH thread ? Logic would suggest LH but, the Flywheel nut on the other side is LH thread, which is odd considering the crank rotation is clockwise.
Must find out somehow or other, before I end up mangling the threads by turning it the wrong way !!