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 timing and smooth operation. Always confirm correct sizing and placement before installation.

FAQ

Q: What are early signs this key might be failing?
A: You may notice slight timing issues, inconsistent running, or trouble starting.

Q: Can I reuse this part if it looks fine?
A: It’s better to replace it—small wear isn’t always visible but can still cause problems.

Q: Does installing this require special tools?
A: Basic tools usually work, but proper flywheel removal tools may be needed depending on location.

Q: How should it sit once installed?
A: It should be snug in the slot and sit evenly without tilting or sticking up.

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

• Supersessions
  90280-04052-00