What is the age of your 80hp 912. Early 912 engines have a different prop flange than newer models. When Rotax introduced the 100hp ULS they changed the flange on all 912 engines. Most prop hubs are now for the newer bolt pattern. Warp and GSC still make hubs for the older engines. Whirlwind along with many others do not make hubs that fit the older bolt pattern.

Ralph