Magnetic Oil Drain Plug – Fits Mercury & MerCruiser Outboards & SternDrives (Replaces 8M0058389)

Magnetic Oil Drain Plug – Fits Mercury & MerCruiser Outboards & SternDrives (Replaces 8M0058389)

This magnetic oil drain plug is designed to replace the standard gear lube fill or vent plug on a wide range of Mercury Outboards, Mariner Outboards, and MerCruiser SternDrives. It is compatible with most models that utilize a 3/8-16 drain/fill screw, with the exception of the Verado series. For sterndrives, it fits MC-1, Alpha 1, Gen II, TR, and TRS models that require magnetic plugs.

This component directly replaces OEM and aftermarket part numbers, including Mercury/QuickSilver 8M0058389, Mercury 67892A1, 67892A06, 67892A05, and 14834A1, as well as GLM 21731, Sierra 18-2375, 18-23751-9, and Mallory 9-72651.

• Installation Type: Threaded plug with a pre-installed seal.
• Key Feature: Built-in magnet captures ferrous metal particles, protecting internal gears from damage.
• Connection Thread: 3/8-16 UNC standard thread for a secure fit.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

For Johnson/Evinrude owners, here’s a guide to help you identify your engine’s serial/model: Johnson Serial Number Guide.

Technical Specifications

Package Contents

1 x Lower Unit Gear Lube Drain and Fill Hole Screw and Seal (8M0058389)

Installation Guide

1. Ensure the engine is off and the boat is secure on a level surface.
2. Position a suitable drain pan below the lower unit's drain/fill hole.
3. Using the correct size wrench, carefully loosen and remove the old drain plug.
4. Allow the old gear lube to drain completely.
5. Inspect the old plug's magnet for excessive metal shavings, which can indicate gear wear.
6. Clean the area around the drain hole to ensure a good seal.
7. Install the new magnetic drain plug with its seal, hand-tightening first.
8. Tighten the plug to the manufacturer's recommended torque specification. Do not overtighten.
9. Refill the lower unit with the correct type and amount of gear lube through the vent hole as per your service manual.
10. Clean up any spills and dispose of the old lube responsibly.

Troubleshooting & FAQ

Q: How do I know if this drain plug will fit my engine?
A: This plug is compatible with most Mercury and Mariner outboards using a 3/8-16 thread (excluding the Verado series), and many MerCruiser sterndrives like the MC-1, Alpha 1, and Gen II. To be certain, always cross-reference your original part number with our list (e.g., 8M0058389, 18-2375).

Q: What is the purpose of the magnet?
A: The integrated magnet captures fine metallic particles (ferrous debris) circulating in your gear lube. This helps prevent premature wear and damage to the internal gears by keeping the oil cleaner.

Q: How can I tell if my old plug needs replacing?
A: Inspect your current drain plug during each gear lube change. Signs it needs replacement include stripped threads, a damaged seal that causes leaks, or a weakened magnet. A large amount of metal shavings on the magnet is a sign of internal gear wear that needs further inspection.

Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.