Gearbox Drain Fill Screw + 2 Washers For Yamaha Outboard 90340-08002 M8 Plug
90340-08002
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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.
Key Features
- ✔ Marine-Grade Stainless Steel: Superior rust resistance.
- ✔ Complete Kit: Includes 1 plug and 2 replacement washers.
- ✔ Direct Fit: Replaces common M8 Yamaha gearcase plugs.
- ✔ 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 £150 the shipping is £6.99.
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