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

FAQ

Q: What are common signs this woodruff key is failing?
A: You may notice timing issues, rough running, or the engine may not start.

Q: Can a slightly worn key still cause problems?
A: Yes, even minor wear can throw off alignment and affect performance.

Q: Do I need to replace it every time I remove the flywheel?
A: Not always, but if there’s any wear, it’s best to replace it while you’re in there.

Q: How should it fit in the keyway?
A: It should sit snug and flush without rocking or sticking out unevenly.

Q: What’s the most common cause of failure?
A: Improper torque or components slipping under load are the main reasons.