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 timing and rotational accuracy are critical. Always verify correct sizing and application before installation.

FAQ

Q: What happens if this woodruff key is worn or damaged?
A: You may see timing issues, rough running, or the engine may not start at all.

Q: Can I reuse an old woodruff key?
A: It’s best not to—wear isn’t always obvious, and a new one avoids future problems.

Q: Does installing this require special tools?
A: Basic tools usually work, but you may need a flywheel puller depending on access.

Q: How should the key sit in the slot?
A: It should sit snug and flush, without rocking or sticking out unevenly.

Q: What typically causes a woodruff key to fail?
A: Improper torque, sudden impact, or components slipping out of alignment are common causes.

• Supersessions
  90280-16053-00, 90280-05048-00, 90280-05013-00, 214-11545-01-00