fly boy2,

Is the prop touching the cutouts on the spinner cone? I can't see what would cause the backplate to bow out like that unless the cone is pushing back on the prop itself. No part of the prop should touch the cone. If the cutouts are too small, you have to enlarge them so that the prop does not touch the spinner cone. The order of installation is backplate, prop, prop washer, prop nut, then spinner cone.

Jesse