40 HP-125 HP Mercury Mariner Outboard Gearbox Lower Unit Seal Kit 26-43035A4 18-2626

Gearbox / Lower Unit Seal Kit for Mercury & Mariner Outboards

Marine-grade aftermarket gear housing / lower unit seal kit for selected Mercury and Mariner 40 HP–125 HP outboards.

Suitable for a wide range of selected 2-stroke, 4-stroke, BigFoot and 4-cylinder gearcase applications.

Replaces Mercury / Mariner 26-43035A4 and earlier versions of the same seal kit.

Fitment

Fits selected Mercury & Mariner outboards using the compatible gear housing.

2-Stroke Applications

Selected:

• 40 HP

• 45 HP

• 50 HP

• 55 HP

• 60 HP

• 65 HP

• 70 HP

• 75 HP

• 80 HP

• 90 HP

• 100 HP – 4 Cylinder

• 115 HP – 4 Cylinder

• 125 HP – 4 Cylinder

Common 100 / 115 / 125 HP 2-Stroke Applications

Suitable for selected 4-cylinder Mercury / Mariner 2-stroke engines, including gearcases equipped with:

• 3-jaw reverse clutch

• 6-jaw reverse clutch

4-Stroke Applications

Used on selected Mercury / Mariner 4-stroke gearcases including:

• 40 HP 4-Stroke

• 50 HP 4-Stroke / BigFoot

• 60 HP 4-Stroke / BigFoot

• 75 HP 4-Stroke

• 80 HP 4-Stroke

• 90 HP 4-Stroke

• 100 HP EFI 4-Stroke

• 115 HP 4-Stroke

Engine / Gearcase Types

Depending on engine serial number, this seal kit is used on selected:

• Mercury Outboard

• Mariner Outboard

• 2-Stroke

• 4-Stroke

• BigFoot

• 3-Cylinder gearcases

• 4-Cylinder gearcases

• 3-jaw reverse clutch gearcases

• 6-jaw reverse clutch gearcases

Replaces / Cross References

Mercury / Mariner

• 26-43035A4

• 43035A4

• 26-43035A3

• 43035A3

• 26-43035A2

• 43035A2

• 26-43035A1

• 43035A1

Aftermarket Cross References

• Sierra 18-2626

• GLM 87590

• Mallory 9-74200

OEM and aftermarket part numbers are used for identification purposes only.

Product Details

• Complete gearbox / gear housing seal kit

• For selected Mercury & Mariner outboards

• Selected 40 HP–125 HP applications

• Selected 2-stroke and 4-stroke engines

• Suitable for selected BigFoot gearcases

• Suitable for selected 3-cylinder and 4-cylinder gearcases

• Replaces Mercury 26-43035A4

• Replaces earlier 26-43035A1 / A2 / A3

• Marine-grade aftermarket replacement

• Designed for lower unit servicing and overhaul

Package Includes

1 × Gear Housing / Lower Unit Seal Kit

Kit contains the seals, O-rings and gaskets supplied for the compatible gear housing application.

IMPORTANT – Gearcase & Serial Number Must Be Checked

This kit does NOT fit every Mercury or Mariner 40–125 HP outboard.

Mercury used different lower units and seal kits on engines with the same horsepower and similar years.

Compatibility depends on:

• Exact horsepower

• Engine model

• Engine serial number

• 2-stroke or 4-stroke

• Number of cylinders

• Standard or BigFoot gearcase

• Gearcase configuration

• Original seal kit / part number

100 HP / 115 HP / 125 HP 2-Stroke

This kit is particularly common on selected 4-cylinder 100 HP, 115 HP and 125 HP Mercury / Mariner 2-stroke outboards and can be used with compatible 3-jaw or 6-jaw reverse clutch gearcases.

Do not order this kit based on horsepower alone.

If you are unsure, send SSI Marine your engine serial number before ordering and we can check the correct gearbox seal kit.

Why Buy From SSI Marine?

• Workshop-tested aftermarket & OEM-spec parts

• More than 10 years supplying outboard parts

• UK stock

• Same-day dispatch before 1 PM Mon–Fri

• Royal Mail Tracked 24

• Collection from Leigh, Greater Manchester

• Technical support available

Buyer Responsibility

Please confirm compatibility with your exact engine model, serial number and gearcase before purchase.

A similar-looking seal or matching horsepower does not guarantee that this is the correct gearbox seal kit.