I'm just breaking in my new .72 Saito 4 stroke. Sometimes it backfires and the prop nut and the stop nut both loosen up. I try to tighten them as tight as I can while trying to keep the spinner backplate aligned with the prop ( BTW, it would be nice if APC would work with spinner manufacturers to fit a spinner to their props).

Anyone else have this problem? Any suggestions on how to keep the nut from loosening?

Thanks,
Dan