Lower Unit Seal Kit – Fits Suzuki 40-60HP & OMC/BRP 40-50HP (Replaces 25700-88L00, 25700-88L03, 5031456)
Lower Unit Seal Kit – Fits Suzuki 40-60HP & OMC/BRP 40-50HP (Replaces 25700-88L00, 25700-88L03, 5031456) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Lower Unit Seal Kit – Fits Suzuki 40-60HP & OMC/BRP 40-50HP (Re...
Product Details
This aftermarket Lower Unit Seal Kit is engineered to service the gearcase on a wide range of Suzuki and Johnson/Evinrude outboard motors. It provides a direct-fit replacement for Suzuki 40-60HP 4-Stroke models from 1999 to present and Johnson/Evinrude 40-50HP 4-Stroke engines manufactured between 1999 and 2006.
This comprehensive kit serves as a direct replacement for Suzuki part numbers 25700-88L00, 25700-88L03, and OMC/BRP number 5031456, among others. See the part number matrix for a full list of interchange references.
- Engineered to meet or exceed OEM specifications for fit and function.
- Provides all necessary seals to prevent water intrusion and oil leaks in the lower unit.
- Professional installation is highly recommended to ensure a proper seal and long-term performance.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Suzuki | 25700-88L00 | 25700-88L03 | |
| Suzuki | 25700-88L02 | 25700-88L03 | |
| Suzuki | 25700-88L03 | Current OEM Part | |
| Suzuki | 25700-88400 | ||
| Suzuki | 25700-94400 | ||
| OMC / BRP | 5031456 | Johnson / Evinrude | |
| Sierra Marine | 18-8337 | Aftermarket |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits various 4-stroke outboards from Suzuki, including the popular DF series.
Also compatible with select Johnson/Evinrude (OMC/BRP) 4-stroke models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Suzuki | DF40 | 40 | 4-Stroke | 1999–2010 | 25700-88L00/25700-88L03 | Original part superseded by 25700-88L03 |
| Suzuki | DF50 | 50 | 4-Stroke | 1999–2010 | 25700-88L00/25700-88L03 | Original part superseded by 25700-88L03 |
| Suzuki | DF40A | 40 | 4-Stroke | 2010–Present | 25700-88L00/25700-88L03 | Original part superseded by 25700-88L03 |
| Suzuki | DF50A | 50 | 4-Stroke | 2010–Present | 25700-88L00/25700-88L03 | Original part superseded by 25700-88L03 |
| Suzuki | DF60A | 60 | 4-Stroke | 2010–Present | 25700-88L00/25700-88L03 | Original part superseded by 25700-88L03 |
| Suzuki | DT40C | 40 | 2-Stroke | 1984–1998 | 25700-94400 | Older models |
| Johnson/Evinrude | E40/J40/BJ40 | 40 | 4-Stroke | 1999–2006 | 5031456 | 3 cylinder models |
| Johnson/Evinrude | E50/J50/BJ50 | 50 | 4-Stroke | 1999–2006 | 5031456 | 3 cylinder models |
Technical Specs
- Product Type
- Lower Unit/Gearcase Seal Kit
- Weight
- 0.22 lb (0.1 kg)
- Product Dimensions
- 7.13" x 6.0" x 1.13"
- Warranty
- Manufacturer standard warranty
What’s in the Box
- 1 x Lower Unit Seal Kit (Replaces 25700-88L03)
Installation Notes
Replacing lower unit seals is a critical repair that requires specialized tools and mechanical expertise. To prevent gearcase damage from improper installation, professional installation by a qualified marine mechanic is strongly recommended. The process typically involves draining the gear lube, removing the propeller, disassembling the lower unit bearing carrier, replacing all seals and O-rings, and reassembling with proper torque specifications and a pressure test.
Troubleshooting & FAQ
Which engines does this seal kit fit?
It's designed for Suzuki 40-60HP 4-Stroke models (1999–Present) and Johnson/Evinrude 40-50HP 4-Stroke models (1999–2006). Always verify your specific model and year in the compatibility table to ensure a perfect match.
What are the signs of a failing lower unit seal?
Common indicators include a milky or cloudy appearance in your gear lube (due to water intrusion), visible gear oil leaks around the propeller shaft or driveshaft, or a burnt smell from the lower unit. Routine inspection is key.
My OEM part number is 25700-88L00. Is this kit compatible?
Yes, this kit directly replaces Suzuki part numbers 25700-88L00, 25700-88L02, and the current 25700-88L03. It also serves as an equivalent for several other part numbers listed in our Part Number Matrix.
How often should I replace my gearcase seals?
It is good practice to inspect seals whenever you change your lower unit gear lube (typically annually or every 100 hours). Seals should be replaced if there are any signs of leakage or water intrusion, or as part of a major service every 3-5 years, depending on usage and conditions.
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.
Payment & Security
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