Yamaha - Woodruff Key Flywheel & Shaft Alignment 90280-03047-00. Overview. This woodruff key is a small part that plays a big role in keeping your engine running right. It holds critical components in position so timing stays locked in every time you turn the key. I've come across engines with strange performance issues that traced back to a worn or partially sheared key like this. It's simple, but if it's not right, nothing else lines up the way it should.. Key Features. Precise Component Indexing - Keeps flywheel and shaft aligned for proper engine timing.. Secure Anti-Slip Fit - Prevents movement between mating parts under load.. Durable Metal Construction - Built to handle torque and repeated engine cycles.. Yamaha-Specific Sizing - Designed to fit factory keyways without modification.. Engine & Boat Compatibility. Commonly used across Yamaha outboards in flywheel, crankshaft, and other keyed shaft applications. Supports systems where accurate alignment is critical for timing and s