I have a question about installing a prop. on an OS engine (0.55AX). The engine is installed on an airboat so I'm not very familiar with the best way to address this issue. I figured the rc plane guys would be the best experts. I'm installing an APC prop. with a tru-turn aluminum spinner. I can't get the adapter nut to be tight enough so that the prop. doesn't spin on it's own while the motor shaft remains stationary. I believe the nut is bottoming out on the motor shaft and that's why I can't get the prop to stop moving. Does anyone have any suggestions on what I could use as a safe spacer? Thanks