Lower Unit Seal Kit – Fits Mercury Force 40-50 HP (1992-1994) (Replaces 26-820645A1)

$14.50

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Product Details

This aftermarket Lower Unit Seal Kit – Fits Mercury Force 40-50 HP (1992-1994) contains all necessary seals for a complete lower unit gearcase rebuild. It is designed for Mercury Force 40 HP and 50 HP, 2-stroke outboards manufactured from 1992–1994.

It serves as a direct replacement for Mercury 26-820645A1 and interchanges with other aftermarket numbers including Sierra 18-2636, GLM 87810, and SEI 95-751-11K.

Engineered for direct, hassle-free installation.
Provides a complete set of seals required for a lower unit rebuild.
Manufactured to meet or exceed original equipment specifications.

Part Number Matrix

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

Brand	Part Number	Notes
Mercury	26-820645A1	OEM Part
Sierra	18-2636	Aftermarket Replacement
GLM	87810	Aftermarket Replacement
SEI Marine	95-751-11K	Aftermarket Replacement
Aftermarket	FK1074	Alternate Part Number

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Force models, please verify your engine's serial number falls within the specified range to ensure correct fitment.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Force	40 HP	40	2-Stroke	1992–1994	26-820645A1	Serial: 0E000001 THRU 0E093699
Force	50 HP	50	2-Stroke	1992–1994	26-820645A1	Serial: 0E000001 THRU 0E093699

Technical Specs

Product Type: Lower Unit/Gearcase Seal Kit
Installation: Direct Replacement
Dimensions: 7.13" × 6.0" × 1.0"
Weight: 0.03 kg (0.06 lb)
Warranty: Varies by manufacturer
OEM Reference: 26-820645A1
GTIN: 745061330955

What’s in the Box

A complete set of seals and o-rings required for a lower unit gearcase rebuild, equivalent to OEM kit 26-820645A1.

Installation Notes

Completely drain all oil from the gearcase before beginning disassembly.
Carefully disassemble the lower unit, taking photos and keeping all hardware organized.
Remove all old seals and o-rings. Thoroughly clean the seal seating surfaces, removing any old sealant or corrosion.
Compare the new seals from the kit with your old ones to confirm correct placement.
Lightly lubricate the new seals and o-rings with marine grease before installation to prevent damage.
Use a correctly sized seal driver or socket to press the new seals into place evenly and without damage.
Reassemble all components, ensuring bolts are torqued to the manufacturer's recommended specifications.
Refill the gearcase with the correct type and amount of fresh lower unit oil and check for leaks.

Troubleshooting & FAQ

How do I know if this seal kit fits my engine?

This kit fits Mercury Force 40 HP and 50 HP 2-stroke outboards from 1992–1994 with serial numbers from 0E000001 through 0E093699. Always verify your OEM part number is 26-820645A1 and check the compatibility table details before ordering.

What are the signs my lower unit seals are failing?

The most common signs of seal failure are milky or creamy-looking gear lube (due to water intrusion), visible oil leaking from the propeller shaft area, or a consistent drop in gear oil level.

How often should lower unit seals be replaced?

As a best practice, you should inspect your gear lube after every season. We recommend replacing lower unit seals every 2-3 years as preventative maintenance, or immediately if you notice signs of water contamination or leaks.

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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