90430-08003 Yamaha Gearbox Drain Gasket | Genuine OEM Yamaha Outboard Part

🔧 Product Description

Genuine Yamaha Gearcase Drain and Vent Screw Gasket - Part Number: 90430-08003

A genuine Yamaha fibre sealing washer for lower-unit gear-oil drain, fill and vent screws.

The gasket seals beneath the screw head and should normally be replaced whenever the plug is removed to prevent lubricant loss or water entry.

⚙️ Key Features

• Genuine Yamaha OEM gearcase screw gasket
• Correct current Yamaha part number 90430-08003
• Supersedes earlier washer 90430-08020
• Used on Yamaha lower-unit drain and vent screws
• Two washers commonly required during a gear-oil change

🚤 Compatibility

Commonly used on

• Yamaha outboard lower-unit drain and vent screws
• Gearcase lubricant servicing

Typically suits

• Engine models:
• Yamaha portable outboards
• Yamaha mid-range outboards
• Yamaha V6 and V8 high-horsepower outboards
• Yamaha two-stroke, HPDI, four-stroke, VMAX SHO and XTO gearcases using the matching drain screw
• Conventional and counter-rotation Yamaha lower units
• HP Range: Applicable Yamaha outboards from small portable engines through high-horsepower models
• System Type: Lower-unit lubricant drain, fill and vent screw
• Service Quantity: Commonly two gaskets per gear-oil change.

🔌 Function

The gasket forms a fluid-tight seal beneath the drain or vent screw, retaining gear lubricant and preventing water intrusion.

⚠️ Common Signs of Failure

• Gear oil around the screw
• Milky or water-contaminated lubricant
• Washer is flattened, cracked or missing
• Gearcase fails pressure testing at the plug
• Leakage begins after an oil change

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 90430-08003 → Supersedes 90430-08020
• 90430-08020 earlier OEM gearcase gasket reference

OEM / Related Numbers

• 90430-08003
• 90430-08003-00
• 90430-08020
• Yamaha gear-oil drain-plug washer
• Yamaha vent-plug sealing gasket

Aftermarket / Verified Equivalents

• Aftermarket Yamaha-pattern black fibre drain-plug washer
• Replacement gasket supplied in Yamaha-pattern gear-oil service kits

📦 Condition

• Genuine Yamaha part
• Brand new
• Supplied in original or equivalent packaging