Propeller Shaft Oil Seal – Fits Mercury/Mariner 30-125 HP (Replaces 26-70081)

Propeller Shaft Oil Seal – Fits Mercury/Mariner 30-125 HP (Replaces 26-70081)

This propeller shaft oil seal is designed for a wide range of Mercury, Mariner, and Force outboard engines from 30 to 125 HP, covering models from 1978 to the present. It ensures a precise fit for the lower unit gearcase, preventing water intrusion and retaining essential gear oil.

This component is a direct replacement for Mercury part 26-70081, Sierra 18-2053, GLM 85530, Quicksilver 26-70081, and UAN Marine 91255-zw1-003.

• Primary Function: Prevents water from entering the gearcase and stops gear lube from leaking out.
• Installation Location: Mounts in the lower unit (gearcase) around the propeller shaft.
• Durable Construction: Made from high-quality Nitrile Rubber (NBR) for reliable sealing and long service life.

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.

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Propeller Shaft Oil Seal (Replaces 26-70081)

Installation Guide

1. Position the outboard in a secure, upright position. Place a drain pan under the lower unit.
2. Remove the lower drain screw and the upper vent screw to drain the gearcase oil completely.
3. Remove the propeller, thrust washer, and any associated hardware, exposing the bearing carrier and prop shaft.
4. Carefully remove the old oil seal from the bearing carrier, taking care not to scratch the housing. A seal puller tool is recommended.
5. Thoroughly clean the seal housing area to remove any old sealant, corrosion, or debris.
6. Apply a light coat of marine grease or gear oil to the outer edge of the new seal and the housing.
7. Gently press the new seal into place, ensuring it is seated evenly and to the correct depth. A socket or seal driver of the appropriate diameter can be used to tap it in squarely.
8. Reinstall the propeller hardware and propeller.
9. Reinstall the lower drain screw with a new gasket. Fill the gearcase with fresh gear lube through the drain hole until it flows out of the upper vent hole.
10. Reinstall the upper vent screw, clean up any spilled oil, and check for leaks after a short period.

Troubleshooting & FAQ

How do I confirm this fits my engine?

First, check the "Part Number Cross-Reference" table to see if your existing part number is listed. Second, review the "Compatible Engine Models" table to ensure your specific engine model and year are included. Matching both is the best way to guarantee fitment.

What are the signs of a failing propeller shaft seal?

Common signs include visible gear oil leaking from the propeller area or a milky, white appearance in your gearcase oil when you drain it, which indicates water contamination.

What material is this seal made from?

This seal is constructed from Nitrile Rubber (NBR), a durable material known for its excellent resistance to oil, fuel, and other chemicals, providing a reliable and long-lasting seal.

OEM vs. Aftermarket?

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.

How fast do you ship and how much does it cost?

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.

What is your warranty and return policy?

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.