Propeller Bore Reducing Bushing 

Anchor Bushing propeller bore reducing bushings will adapt a inboard propeller with a larger bore to a smaller diameter shaft. 

• Bushings are available in both bronze and nylon
• Comes complete with a brass step key
• Fits standard SAE propeller shaft taper
• 1:16 taper rate

The nylon bushing seem to work just fine for low horsepower applications.  For high horsepower usage the bronze bushing is a better choice.