Yamaha - Woodruff Key Flywheel & Shaft Alignment 90280-04008-00. Overview. This woodruff key is one of those small parts that keeps everything turning the way it should without much attention. It locks your flywheel or gear into the correct position so timing stays consistent under load. I've seen engines run rough or lose timing just because this piece was worn or slightly off. It's simple, but it's one of those parts you don't want to overlook when you're working on your motor.. Key Features. Accurate Component Alignment - Keeps rotating parts properly indexed for correct engine timing.. Secure Locking Fit - Prevents slipping between the shaft and connected components.. Durable Metal Construction - Built to handle engine torque and repeated use.. Factory-Specific Dimensions - Matches Yamaha keyways for a precise, reliable fit.. Engine & Boat Compatibility. Used across a variety of Yamaha outboards in flywheel, crankshaft, and other keyed shaft applications. Supports systems where mai