Standard right hand thread, you will need to lock the crank on the output side, with stilsons or something similar. and the top nut on the crank will be tight, also the flywheel will be on tight and you should use a bolted puller to remove it but you can remove it by placing a large flat screwdriver between the engine case and the flywheel and giving the flywheel a couple of sharp taps with a hammer.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix lawn mowers.