Description

Mercury MerCruiser Seal – 8M0058391

Ensure a proper seal when servicing your sterndrive or outboard gearcase with the Mercury MerCruiser Seal 8M0058391. This genuine Mercury / Quicksilver OEM gearcase drain screw seal (washer) is used with the gear lube drain and fill screws to create a watertight seal and prevent water intrusion into the gearcase.

The seal is made from rubber-coated stainless steel, providing a durable sealing surface that helps maintain proper gear oil containment and prevents leaks during operation.

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Key Features

• Genuine Mercury Marine / Quicksilver OEM gearcase seal

• Rubber-coated stainless steel washer design

• Provides a watertight seal for gearcase drain/fill screws

• Helps prevent water intrusion into the gearcase

• Durable construction designed for marine environments

• Recommended replacement when performing gear lube changes

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Part Details

OEM Part Number: 8M0058391
Mercury Reference Number: 26-8M0058391
Product Type: Gearcase drain screw seal / washer

Material: Rubber-coated stainless steel
Application: Gearcase drain and fill screw sealing washer
Typical Packaging: Often sold in packs of 2

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Compatible Mercury & MerCruiser Engines

Used on gearcase drain and fill screws with 3/8-16 threads, including:

Mercury Outboards

• Mercury 2.5HP – 400HP outboards

• Mercury Two-Stroke outboards

• Mercury FourStroke outboards

• Mercury Pro XS outboards

• Mercury Verado outboards

MerCruiser Sterndrives

• Alpha One

• Alpha One Gen II

• Bravo One

• Bravo Two

• Bravo Three

This seal is compatible with most Mercury and Mariner outboards and all MerCruiser sterndrives using 3/8-16 gearcase drain/fill screws.

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Function

The drain screw seal is installed under the gearcase drain or fill screw to prevent leaks and stop water from entering the gearcase.

Replacing the seal during gear lube service helps:

• Prevent gear oil leaks

• Stop water intrusion into the gearcase

• Maintain proper lubrication of internal gears

• Protect the sterndrive or gearcase from internal damage

Even a small leak can allow water to mix with gear oil, which can cause gearcase corrosion or gear failure.

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Important Compatibility Note

Gearcase drain screw seals should always be replaced during gear lube changes to maintain a proper seal. Always verify the gearcase drain screw size (3/8-16) and engine or drive serial number before ordering to ensure correct fit.

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Shipping: Ships same or next day for fast Canada wide shipping.