Sierra 18-3302 Woodruff Key (6E5) Yamaha 90280-04

Keep your Yamaha outboard running smoothly with the Sierra 18-3302 Woodruff Key, a precision-engineered replacement designed specifically for the 6E5 engine family. This essential component slots into the crankshaft or flywheel assembly, ensuring a secure, slip-free connection that transmits power reliably under high RPMs and demanding marine conditions. Crafted from high-grade steel with a hardened finish, it resists wear from vibration, corrosion, and saltwater exposure—common culprits in outboard failures.

Why Your Yamaha 6E5 Needs a Reliable Woodruff Key

A worn or sheared Woodruff Key can lead to intermittent power loss, starter issues, or even complete engine seizure. In Yamaha's 6E5 series—popular in compact tillers and portable outboards—this half-moon-shaped key aligns the flywheel precisely with the crankshaft, maintaining ignition timing and preventing destructive slippage. Boaters often overlook it until symptoms like hard starting or erratic revving appear, but proactive replacement during routine servicing prevents costly downtime on the water.

Perfect Fit for Yamaha 6E5 Outboards

Directly replaces OEM Yamaha part 90280-04, this Sierra key matches factory dimensions: typically 1/4" x 3/4" (6mm x 19mm) for seamless integration. It's compatible across various 6E5 variants used in models from the late 1980s through early 2000s, including 5hp and 6hp configurations. Whether you're rebuilding after storage, fixing a slip-damaged flywheel, or upgrading during a powerhead refresh, it drops in without modifications.

• Material: Heat-treated alloy steel for superior shear strength
• Finish: Corrosion-resistant coating ideal for saltwater use
• Design: Tapered profile for easy installation and positive lock

Installation Tips from Seasoned Mechanics

Replacing a Woodruff Key is a straightforward DIY task that takes under 30 minutes with basic tools. First, secure the outboard on a stand and remove the flywheel nut using a marine flywheel puller—avoid hammering to prevent shaft damage. Tap the old key out gently with a brass punch, clean the keyway thoroughly, then press the new Sierra 18-3302 into place with light taps until flush. Reassemble, torque to spec (around 40-50 ft-lbs for most 6E5 flywheels), and test-run to confirm smooth engagement.

Pro Tip: Always inspect the keyway for galling or wear. If elongated, consider a full crankshaft repair to avoid repeat failures.

Durability Built for Real Boating Adventures

Sierra's engineering focuses on marine-grade resilience, outlasting generic keys that crack under load. In real-world tests by coastal anglers and fishing guides, this part withstands thousands of start-stop cycles without deformation. Pair it with fresh gear lube and annual compression checks for peak 6E5 performance, extending your outboard's life through rough chops and long hauls.

Common Issues and When to Replace

Spot early warning signs like a rattling flywheel, delayed starter response, or timing light drift during diagnostics. Overheating from poor cooling or prop strikes often shear these keys first. Stock a spare in your maintenance kit—its compact size makes it a no-brainer for trailering boaters facing remote breakdowns.