228M0058389 Mercury MerCruiser Gearcase Drain Screw | Genuine Quicksilver OEM Part

🔧 Product Description

Genuine Quicksilver Magnetic Gearcase Drain Screw Kit - Part Number: 22-8M0058389

A genuine Quicksilver magnetic lower-unit gear lube drain / fill screw kit used on Mercury, Mariner and MerCruiser gear housings. This kit includes the magnetic 3/8"-16 gearcase drain / fill screw and seal, and is used on MerCruiser stern drives and Mercury / Mariner outboards using the standard magnetic drain or vent screw arrangement, excluding Verado applications where a different plug is specified.

⚙️ Key Features

• Genuine Quicksilver OEM magnetic drain screw kit

• Correct Mercury part number 22-8M0058389

• 3/8"-16 UNC magnetic gear lube drain / fill screw

• Includes sealing washer

• Used on MerCruiser stern drives and Mercury / Mariner outboards where specified

• Helps capture fine metallic wear particles in gear oil

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 22-8M0058389 current OEM magnetic drain screw kit reference

• 22-67892A06 earlier / related magnetic drain screw reference

• 10-79953Q04 related magnetic drain screw kit reference

• 10-79953Q2 related earlier drain screw kit reference

OEM / Related Numbers:

• 22-8M0058389

• 8M0058389

• 228M0058389

• 22-67892A06

• 67892A06

• 10-79953Q04

• 79953Q04

• 10-79953Q2

• 79953Q2

• Magnetic gearcase drain screw

• 3/8"-16 UNC drain screw

• Gear lube fill / vent screw

• 26-8M0204693 related yellow drain screw seal

• 12-8M0187157 related blue drain screw seal

Aftermarket / Verified Equivalents:

• Sierra: 18-2375

• Sierra: 18-23751-9

• Aftermarket magnetic drain screw equivalents exist where matched to Mercury 22-8M0058389

🚤 Compatibility

Commonly used on:

• MerCruiser I, TR, TRS and Alpha Gen I stern drives

• MerCruiser stern drive drain / fill / vent screw applications using 3/8"-16 UNC magnetic screw

• Mercury / Mariner outboard lower units using standard magnetic gear lube fill or vent screws

• Gearcase oil service where magnetic drain screw 22-8M0058389 is specified

Typically suits:

• Engine / drive models:

• MerCruiser I drive magnetic drain screw applications

• MerCruiser TR drive magnetic drain screw applications

• MerCruiser TRS drive magnetic drain screw applications

• MerCruiser Alpha One Gen I drain / fill screw applications

• MerCruiser R / MR / Alpha One drive applications where 22-8M0058389 is specified

• Mercury / Mariner outboard gearcases using standard 3/8"-16 magnetic gear lube drain / vent screw

• Mercury / Mariner 6HP to 300HP outboard lower-unit gearcase applications using standard Mercury magnetic drain / vent screws

• Mercury EFI, DFI and OptiMax gearcase applications where the standard magnetic drain screw is specified

• Mercury high-performance outboard gear housings where 22-8M0058389 is shown in the gear housing diagram

• HP Range: broad Mercury / Mariner outboard gearcase usage where specified

• Drive Type: MerCruiser I / TR / TRS / Alpha Gen I and related standard drain-screw stern drives

• System Type: Magnetic gear lube drain / fill / vent screw kit

• Fitment Note: Not for Verado applications unless the serial-numbered diagram specifically specifies this plug

🔌 Function

The magnetic drain screw seals the gearcase drain / fill opening and captures fine metallic particles suspended in the gear lubricant, helping provide early warning of gear or bearing wear during service.

Common signs of failure:

• Drain screw magnet heavily loaded with metal particles

• Drain screw head rounded or damaged

• Gear oil leak around drain / fill screw

• Sealing washer crushed, missing or reused

• Thread damage in screw or gearcase

• Replacement required during lower-unit or sterndrive service

📦 Condition

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging