Lower Unit Seal Kit – Fits Mercury/Mariner Outboard 30-125 HP (Replaces 26-43035A4)

Vendor: JLM Marine
Availability: In Stock
Product Type: Seal Kit
$67.15
$67.15
Subtotal: $67.15

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Lower Unit Seal Kit – Fits Mercury/Mariner Outboard 30 - 125 HP (Replaces 26 - 43035A4) - JLM Marine Boat Parts Limited

Lower Unit Seal Kit – Fits Mercury/Mariner Outboard 30-125 HP (Replaces 26-43035A4)

$67.15

Lower Unit Seal Kit – Fits Mercury/Mariner Outboard 30-125 HP (Replaces 26-43035A4)

$67.15

Lower Unit Seal Kit – Fits Mercury/Mariner Outboard 30-125 HP (Replaces 26-43035A4)

This lower unit seal kit is designed for a wide range of Mercury/Mariner 30-125 HP 2-stroke and 4-stroke outboards (1991-2010). It is compatible with lower units featuring either a 3-jaw or 6-jaw reverse clutch. This kit fits USA serial numbers 0B209468 and newer, and Belgium serial numbers 9523034 and newer.

This kit directly replaces Mercury OEM part numbers 26-43035A4, 26-43035A3, 26-43035A2, and 26-43035A1. It also serves as an aftermarket replacement for Sierra 18-2626, GLM 87590, and Mallory 9-74200.

  • Installation: Designed for direct replacement of the original seals.
  • Compatibility: Fits lower units with either 3-jaw or 6-jaw reverse clutches.
  • Complete Kit: Includes all necessary seals and gaskets for a lower unit rebuild.

Part Number Cross-Reference

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

Brand Part Number
Mercury 26-43035A4
Mercury 26-43035A3
Mercury 26-43035A2
Mercury 26-43035A1
Sierra 18-2626
GLM 87590
Mallory 9-74200

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.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Mercury/Mariner 2-Stroke 100/115/125 2-Stroke 1991+ 26-43035A4 USA 0B209468 and newer, Belgium 9523034 and newer, with either 3 or 6 jaw reverse clutch
Mercury/Mariner 4-Stroke BIGFOOT 50 4-Stroke 1991-2010 26-43035A4
Mercury/Mariner 3-cyl BIGFOOT 60 4-Stroke 1991-2010 26-43035A4
Mercury/Mariner 3-cyl 70 4-Stroke 1991-2010 26-43035A4 USA 0A996142+ / BEL 9483121+
Mercury/Mariner 3-cyl 75 4-Stroke 1991-2010 26-43035A4 USA 0C222000+ / BEL 9589039+
Mercury/Mariner 3-cyl 80/90 4-Stroke 1991-2010 26-43035A4
Mercury/Mariner 4-cyl 100/115/125 4-Stroke 1991-2010 26-43035A4
Mercury/Mariner 3-cyl 30-90 2-Stroke 1991-2010 26-43035A4 As reported by EMP
Mercury/Mariner 4-cyl 45-90 2-Stroke 1991-2010 26-43035A4 As reported by EMP
Force Outboard 30-125 2-Stroke 1991-1999 26-43035A4 Compatibility reported by various retailers

Technical Specifications

Specification Value
Product Type Lower Unit/Gearcase Seal Kit
Installation Direct replacement
Other Technical Attributes For applications with either 3-jaw or 6-jaw reverse clutch

Package Contents

  • 1 x Lower Unit Seal Kit (Replaces 26-43035A4), including all necessary seals and gaskets for service.

Installation Guide

  1. Drain the gearcase oil completely into a suitable container.
  2. Remove the propeller and then unbolt and detach the lower unit from the outboard's driveshaft housing.
  3. Carefully disassemble the gearcase, removing the bearing carrier and old seals. Take photos to remember the assembly order.
  4. Thoroughly clean all components and mating surfaces, removing any old sealant or gasket residue.
  5. Lubricate the new seals with marine grease and install them into their respective bores, ensuring they are seated properly and facing the correct direction.
  6. Install the new gaskets and reassemble the lower unit components.
  7. Torque all bolts to the manufacturer's specified values.
  8. Reinstall the lower unit onto the outboard and attach the propeller.
  9. Refill the gearcase with the correct type and amount of fresh gear lube before operation.

Troubleshooting & FAQ

Q: How do I confirm this seal kit fits my specific Mercury outboard?

A: Check your engine's serial number. This kit is confirmed to fit USA models 0B209468 and newer and Belgium models 9523034 and newer. It is designed for the wide range of 30-125 HP 2-stroke and 4-stroke models listed in our compatibility table.

Q: What are the signs that my lower unit seals are failing?

A: Common signs of seal failure include milky or watery gear oil, which indicates water intrusion. You may also notice visible oil leaks around the propeller shaft or driveshaft, or find a metallic sheen in the drained oil, suggesting wear from poor lubrication.

Q: Is this kit compatible with both 3-jaw and 6-jaw clutches?

A: Yes. This kit is specifically designed to work for lower units equipped with either the 3-jaw or 6-jaw reverse clutch, making it a versatile replacement for the specified HP and year range.

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.

We can ship to virtually any address in the world with free shipping available for most regions.

For our typical US and Canadian customers , our shipping timeframes are as follows:

  • Amazon FBA: orders will be delivered within 1-5 business days after placing the order (during certain special periods such as major promotions, Christmas, etc., the delivery time of Amazon FBA may be affected).
  • US warehouse shipment: orders will be delivered within 5 days after placing the order.
  • China warehouse shipment: orders will be delivered about 12 days after placing the order.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

Founded in 2002, JLM Marine has established itself as a dedicated manufacturer of high-quality marine parts, based in China. Our commitment to excellence in manufacturing has earned us the trust of top marine brands globally.

As a direct supplier, we bypass intermediaries, which allows us to offer competitive prices without compromising on quality. This approach not only supports cost-efficiency but also ensures that our customers receive the best value directly from the source.

We are excited to expand our reach through retail channels, bringing our expertise and commitment to quality directly to boat owners and enthusiasts worldwide.

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