Yamaha - Woodruff Key Flywheel & Shaft Alignment 90280-05001-00. Overview. This woodruff key is one of those parts that keeps everything lined up behind the scenes. It holds your flywheel and shaft in the exact position they need to stay in so timing doesn't drift. I've seen engines chase all kinds of issues that ended up being nothing more than a worn or slightly sheared key. It's a small piece, but it's critical to how the motor runs every time you turn it over.. Key Features. Precise Shaft Alignment - Keeps rotating components indexed correctly for proper engine timing.. Slip-Resistant Fit - Prevents movement between mating parts under load.. Durable Metal Build - Designed to handle torque and repeated engine cycles.. Factory-Matched Dimensions - Fits Yamaha keyways properly without modification.. Engine & Boat Compatibility. Used across a range of Yamaha outboards in flywheel, crankshaft, and other keyed shaft applications. Essential for maintaining alignment in systems where timin