Gearcase Seal Kit – Fits Mercury/Mariner Outboards 6-15 HP (Replaces 26-41365A3)

$36.90 $59.00

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Gearcase Seal Kit – Fits Mercury/Mariner Outboards 6-15 HP (Replaces 26-41365A3) is backordered and will ship as soon as it is back in stock.

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Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This aftermarket Gearcase Seal Kit is designed for Mercury and Mariner outboard lower units. It fits a wide range of models including 6–15 HP 2-stroke (1986–2005) and select 8–15 HP 4-stroke outboards manufactured up to 2005.

It serves as a direct cross-reference for Mercury part numbers 26-41365A3, 26-41365A2, and 26-41365A1, and interchanges with GLM 87576 and SEI 95-261-11K.

Installs in the lower unit/gearcase section.
Engineered for gasoline-powered outboard motors.
Includes all necessary seals for a complete lower unit service.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number	Notes
Mercury	26-41365A3	OEM Reference
Mercury	26-41365A2	Superseded by 26-41365A3
Mercury	26-41365A1	Superseded by 26-41365A3
GLM	87576	Aftermarket Interchange
SEI	95-261-11K	Aftermarket Interchange

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	Outboard	6	2-Stroke	1986–2005	26-41365A3	Serial 9461526-0T800999
Mercury	Outboard	8	2-Stroke	1986–2005	26-41365A3	Serial 9461526-0T979999
Mercury	Outboard	8	4-Stroke	Up to 2005	26-41365A3	Serial 0T980000-1B000001+
Mercury	Outboard (BODENSEE)	8	4-Stroke	International	26-41365A3	Serial 0H000058+
Mercury	Outboard	9.9	2-Stroke	1986–2005	26-41365A3	Serial 9461526-0T979999
Mercury	Outboard	9.9	4-Stroke	Up to 2005	26-41365A3	Serial 0T980000-1B000001+
Mercury	Outboard (323 cc)	9.9	4-Stroke	Up to 2005	26-41365A3	Serial 0G760300-1B226999
Mercury	Outboard (232 cc)	9.9	4-Stroke	Up to 2005	26-41365A3	Serial 0H000058-0H016909
Mercury	XR10	10	2-Stroke	1986–2005	26-41365A3	Serial 9596000-0T979999
Mercury	10 MAGNUM	10	2-Stroke	1986–2005	26-41365A3	Serial 9596000-0T979999
Mercury	10 MARATHON	10	2-Stroke	1986–2005	26-41365A3	Serial 9596000-1B000001+
Mercury	10 SEA PRO	10	2-Stroke	1986–2005	26-41365A3	Serial 9596000-1B000001+
Mercury	10 VIKING	10	2-Stroke	1986–2005	26-41365A3	Serial 0P017000-0P325500+
Mercury	Outboard (International)	13.5	4-Stroke	Up to 2005	26-41365A3	Serial 0P134638+
Mercury	Outboard	15	2-Stroke	1986–2005	26-41365A3	Serial 9542620-1B000001+
Mercury	Outboard	15	4-Stroke	Up to 2005	26-41365A3	Serial 0G590000-1B727495
Mercury	15 MARATHON	15	2-Stroke	1986–2005	26-41365A3	Serial 0G044365-1B000001+
Mercury	15 SEA PRO	15	2-Stroke	1986–2005	26-41365A3	Serial 0G044365-1B000001+
Mercury	15 VIKING	15	2-Stroke	1986–2005	26-41365A3	Serial 0P325500+

Technical Specs

Product Type: Gearcase Seal Kit
Installation: Lower Unit/Gearcase
Fuel Type: Gasoline
Dimensions: 16.0 × 12.0 × 6.0 in
Weight: 0.14 kg (0.31 lb)
Other Technical Attributes: GEARCASE SEAL KIT O/B

What’s in the Box

1 x Complete Gearcase Seal Kit (replaces 26-41365A3)

Installation Notes

Drain the gearcase lubricant completely before beginning disassembly.
Disassemble the lower unit to access the old seals, keeping all hardware organized.
Carefully remove all existing seals, o-rings, and gaskets. Avoid scratching any housing or shaft surfaces.
Thoroughly clean all mating surfaces and inspect for damage, corrosion, or excessive wear.
Lightly lubricate the new seals with marine grease before installation to ensure a smooth fit.
Install the new seals using appropriate seal drivers, ensuring they are seated squarely and to the correct depth.
Reassemble the gearcase components, following the manufacturer'''s torque specifications for all fasteners.
Refill the gearcase with the recommended lubricant to the proper level and check for leaks before operation.

Troubleshooting & FAQ

How do I know if this kit fits my engine?

Check the 'Engine & Model Compatibility' table on this page. It is crucial to match your engine's model, horsepower, and especially the serial number range. If you are still unsure, compare the OEM part number (26-41365A3) with the one listed in your engine's service manual.

What are the signs of a failing gearcase seal?

Common symptoms include a milky or creamy appearance in your gear lube (indicating water intrusion), visible oil leaking from the propeller shaft or driveshaft area, or a persistent need to top off the gear oil. Any of these signs warrant an inspection.

How often should these seals be replaced?

There is no fixed replacement interval. Seals should be inspected for leaks during every gear lube change (annually or every 100 hours) and replaced whenever the lower unit is disassembled for service or if any signs of leakage are found.

Is special equipment required for installation?

Yes, proper installation often requires specialized tools such as seal pullers and seal drivers to remove the old seals and install the new ones without damaging the gearcase housing. We recommend professional installation if you do not have these tools.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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