Gearbox Drain Fill Screw + 2 Washers For Yamaha Outboard 90340-08002 M8 Plug

Gearbox Drain Fill Screw + 2 Washers For Yamaha Outboard 90340-08002 M8 Plug

90340-08002

  • Dispatched in 2-3 days
  • 30 Day Return Policy
  • In stock, ready to ship
  • Backordered, shipping soon
Our stock levels are dynamic and can change frequently. If a product appears to be in stock, it may have already sold out. Please contact us if you have any questions about availability. Thank you for your understanding.

Regular priceΒ£3.99
/
Tax included.

Yamaha Outboard Gearbox Screw Kit

Includes 1x M8 Screw & 2x Sealing Washers

This essential maintenance kit provides a direct replacement for the lower unit gearbox drain and fill plugs on Yamaha outboard engines. Proper sealing of the gearcase is critical to prevent oil leaks and protect your transmission from water contamination. Crafted from high-strength stainless steel, this plug is designed to resist corrosion in both fresh and saltwater environments.

RELIABILITY: Engineered to match OEM dimensions for a perfect watertight seal. Includes high-density fibre washers for professional-grade servicing.

Key Features

  • βœ” Marine-Grade Stainless Steel: Superior rust resistance.
  • βœ” Complete Kit: Includes 1 plug and 2 replacement washers.
  • βœ” Direct Fit: Replaces common M8 Yamaha gearcase plugs.
  • βœ” Precision Machined: Clean threads (M8 x 1.25) for secure fitment.

Technical Specs

Thread Size: M8 x 1.25
Material: 316 Stainless Steel
Screw Length: ~9mm (Threaded Portion)
Washer Material: High-Density Fibre/Nylon

Compatibility / Fitment Guide

Make/System Model Range Notes
Yamaha Outboards 2hp, 4hp, 5hp, 6hp, 8hp, 9.9hp Fits most 2-stroke & 4-stroke units
Yamaha Outboards 15hp to 300hp (F-Series & 2-Stroke) Standard Gearcase M8 Plug
Mariner/Mercury Various (Yamaha-built models) Check M8 thread size before ordering

OEM Cross Reference

Yamaha (Screw) 90340-08002, 90340-08002-00, 90340-08014-00, 90340-08125-00
Yamaha (Gasket) 90430-08020, 90430-08020-00, 90430-08003, 90430-08003-00
Sierra Marine 18-2371, 18-2374, 18-4698
Mercury Marine 22-81924M

Questions & Answers

Is this a genuine original part?

This is a premium quality aftermarket replacement kit from 4Boats, manufactured from marine-grade stainless steel to provide better corrosion resistance than many standard plated plugs.

How do I know if it is compatible?

We recommend checking your engine's part catalog for SKU 90340-08002. This is the standard M8 threaded plug used on almost all Yamaha gearboxes from 2hp up to 300hp.

Why does the kit include two washers?

Most Yamaha outboards have two identical M8 plugs: one for "Draining" (bottom) and one for "Filling/Venting" (top). This kit provides two washers so you can replace the gaskets for both plugs during a single service.

Note: Please verify your original part number against the references above before purchasing. Distributed by 4Boats (4boats.co.uk).

For the products under Β£150 the shipping is Β£6.99.

Free delivery for most items over Β£150.

This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.


Recently viewed

Why choose us

Untitled_1080_x_1080_px_1 - 4Boats

ITS ALL ABOUT THE QUALITY

We source the best products from the Top suppliers only. We’ve taken years of feedback and have doubled down on providing the best service.

Untitled_1080_x_1080_px_2 - 4Boats

TEAMWORK MAKES THE DREAMWORK

Our Suppliers and Partners are joining us in our commitment to challenge the way this industry operates. From product sourcing to fulfilling, they’re the best in the business.

Simple_Image_Play_Built_into_Routine_Cosmetics_TikTok_In-Feed_Ad_1080_x_1080_px_10 - 4Boats

YOU MATTER TO US.

All your orders are personally checked by a member of 4 BOATS and we make sure your orders are dispatched quickly so it arrives to your doorstep ASAP