are you having trouble undoing it? we did ours by hanging a long ring spanner on the nut, and bringing round to rest the handle onto the engine bed. Then flipped the starter over, this undid the crankshaft nut.I think the engine runs anti clock wise as you look at from the front.
We have had a six foot scaffold pole on the spanner and that didn't move it! Starter is knackered anyway. But from your description I would assume the thread is normal right handed, so thanks for that.