Yamaha - Woodruff Key Flywheel & Shaft Alignment 90280-03043-00. Overview. This woodruff key is one of those parts that keeps everything timed right without much attention. It holds your flywheel or gear exactly where it needs to be so nothing shifts when the engine's under load. I've seen engines act completely off just from a slightly worn or sheared key like this. It's small, but it's doing critical work every time the motor is running.. Key Features. Precise Component Alignment - Keeps rotating parts properly indexed for accurate engine timing.. Secure Locking Fit - Prevents slipping between shaft and connected components under load.. Durable Metal Construction - Built to handle torque and repeated engine cycles.. Exact Yamaha Fitment - Matches factory keyway dimensions for proper installation.. Engine & Boat Compatibility. Used across a wide range of Yamaha outboards in flywheel, crankshaft, and other keyed shaft applications. Essential for maintaining alignment in systems where t