Yamaha - Woodruff Key Flywheel & Shaft Alignment 90280-04801-00. Overview. This woodruff key is one of those parts that keeps everything honest inside the motor. It makes sure your flywheel and shaft stay locked in the right position so timing doesn't drift. I've seen engines chase electrical or fuel issues when the real problem was a slightly damaged key. It's a small piece, but it's doing critical work every time you're out on the water.. Key Features. Accurate Component Alignment - Keeps flywheel and shaft indexed correctly for proper timing.. Slip Prevention Fit - Locks components in place to prevent movement under load.. Heavy-Duty Metal Construction - Built to withstand engine torque and repeated use.. Factory-Specific Design - Matches Yamaha keyway dimensions for a clean, secure fit.. Engine & Boat Compatibility. Used across many Yamaha outboards in flywheel, crankshaft, and other keyed shaft applications. Ideal for systems where precise alignment is necessary to maintain engine