90507-921-000 Honda Marine Washer | Genuine OEM Outboard Part

🔧 Product Description

Genuine Honda 8 mm Nylon Gearcase Drain / Vent Plug Washer - Part Number: 90507-921-000

A genuine Honda nylon sealing washer for specified 8 mm lower-unit drain and vent plugs. The nominal washer size is approximately 8 × 14 × 1.5 mm and it should be renewed whenever the gear lubricant is drained.

⚙️ Key Features

• Genuine Honda nylon gearcase sealing washer
• Nominal dimensions: approximately 8 × 14 × 1.5 mm
• Designed for the specified 8 mm drain or vent screw
• Single-use service seal that helps prevent oil leakage and water entry

🚤 Compatibility

Commonly used on

• Honda BF2/BF2.3 and BF5A gearcases using the 8 mm plug
• Honda BF8A/BF9.9A/BF15A and BF8D/BF9.9D/BF15D/BF20D gearcases using the 8 mm plug
• Honda BF25/BF30/BF35/BF40/BF45/BF50 gearcases where the parts diagram lists 90507-921-000
• Honda BF75/BF90 and BF115/BF130 gearcases only where the drain/vent screw uses this 8 mm washer

Typically suits

• HP Range: 2-130 HP across verified 8 mm gearcase-plug applications
• Engine Type: Honda outboard lower-unit drain/vent plug
• Year Range: Application dependent
• Serial / Identification Range: Fitment is controlled by plug diameter rather than horsepower. Confirm the gearcase diagram and 8 mm plug before use.

🔌 Function

Seals the gearcase drain or vent screw to retain lubricant and prevent water entering the lower unit.

⚠️ Common Signs of Failure

• Gear oil seeps from the drain or vent plug
• Milky lubricant caused by water intrusion
• Washer is split, distorted, hardened or missing
• Plug has been removed for a gear-oil change

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 90507-921-000 - current long-running Honda service reference
• No direct supersession to 90601-ZE2-000; that part is a different 12 mm engine-oil washer

OEM / Related Numbers

• 90507-921-000
• 90507921000

Aftermarket / Verified Equivalents

• Generic 8 × 14 × 1.5 mm nylon marine gearcase washers may cross-reference to 90507-921-000
• Material and dimensions must be confirmed before substitution

📦 Condition

• Genuine Honda Marine OEM part
• Brand new
• Supplied in genuine Honda or equivalent protective packaging