I have an Aviastar .46 2-stroke engine for my Northstar kit seaplane. Problem is, it has an 8mm shaft. I can't find any 10" propellers with 8mm shaft holes, but that's the biggest prop an unmodified Northstar can take because of the clearance between nascelle and fuselage. I also can't find any adapters from 8mm to 6mm.

Any suggestions for propellers, and how to get them to fit?