6–15 HP Mercury Mariner Outboard Gearbox Anode 42121Q02 – Zinc / Aluminium

Marine-grade aftermarket gearbox sacrificial anode for selected Mercury and Mariner 6 HP, 8 HP, 9.8 HP, 9.9 HP and 15 HP outboard engines.

Designed to help protect the gearbox, lower unit and underwater metal components against galvanic corrosion.

Replaces Mercury part numbers 42121A1, 42121A2 and 42121Q02.

Available in Zinc or Aluminium.

Choose Your Anode Material

Zinc Anode

• Traditional sacrificial anode material

• Particularly suitable for saltwater applications

• Suitable for installations using zinc anodes

Aluminium Anode

• Marine-grade aluminium alloy

• Suitable for saltwater and brackish water applications

• Suitable for installations using aluminium anodes

Please follow the engine manufacturer's recommendations when choosing anode material.

Fitment

Mercury / Mariner 2-Stroke Outboards

Selected twin-cylinder models:

• 6 HP – 2-Stroke

• 8 HP – 2-Stroke

• 9.8 HP – 2-Stroke

• 9.9 HP – 2-Stroke

• 15 HP – 2-Stroke

Mercury / Mariner 4-Stroke Outboards

Selected standard gearbox models:

• 9.9 HP – 4-Stroke

• 15 HP – 4-Stroke

Important: The 4-stroke applications are for selected standard gearbox models only.

Not Suitable For

• Japanese-built Mariner 2-stroke engines manufactured by Yamaha

• Engines using a different gearbox or anode arrangement

• Other models where the original anode reference does not match

Mercury and Mariner used different gearbox designs across engine generations. Please confirm the original part number before ordering.

Replaces Mercury / Mariner Part Numbers

• 42121A1 – Main product reference

• 42121A2

• 42121Q02

• 97-42121Q02

• 42121A

OEM part numbers are used for identification and compatibility reference only.

Product Details

• Product Type: Gearbox / Lower Unit Anode

• Material: Zinc or Aluminium

• Application: Selected Mercury / Mariner outboards

• Horsepower: 6, 8, 9.8, 9.9 and 15 HP

• Engine Types: Selected 2-stroke and 4-stroke

• Location: Gearbox / Lower Unit

• Purpose: Sacrificial corrosion protection

• Quality: Marine-grade aftermarket replacement

• Quantity: 1 anode

Package Includes

1 × Gearbox Anode

Supplied in your selected material:

• Zinc

• Aluminium

Mounting hardware is not included unless otherwise specified.

Important Compatibility Information

Before ordering, please check:

• Exact Mercury or Mariner engine model

• Engine horsepower and stroke type

• Engine production year

• Engine serial number

• Gearbox type – standard or alternative design

• Original anode part number

• Existing anode shape and dimensions

• Required anode material

If the part looks the same as yours, this does not always mean it is the correct part for your outboard.

If unsure, please contact SSI Marine with your engine model and serial number for assistance.

Why Buy From SSI Marine?

• Workshop-tested aftermarket & OEM-spec parts

• Same-day dispatch before 1 PM Monday–Friday

• Royal Mail Tracked 24

• UK stock – collection available from Leigh, Greater Manchester

• Technical support from experienced outboard specialists

Buyer Responsibility

Please confirm compatibility with your exact Mercury / Mariner engine model, year, serial number and gearbox configuration before purchase.