Lower Unit Seal Kit – Fits Suzuki DF150-DF250 (Replaces 25700-93J00)

$32.55

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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 Lower Unit Seal Kit provides all necessary components to reseal the gearcase on Suzuki DF150, DF175, DF200, DF225, and DF250 4-stroke outboard engines from 2004 to the present. It's engineered to stop leaks and prevent water intrusion, restoring the integrity of your engine's lower unit.

This kit is a direct replacement for Suzuki OEM part number 25700-93J00 and serves as a cross-reference for Sierra Marine part 18-8380.

Installs in the lower unit (gearcase).
Includes all seals required for a complete gearcase rebuild.
Prevents water contamination of gear lube, protecting internal components.

Part Number Matrix

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

Brand	Part Number
Suzuki	25700-93J00
Sierra	18-8380

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Suzuki Outboards: This kit is designed for the specified DF series 4-stroke models. Verify your exact model name (e.g., DF150T, DF200AP) is listed.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.
Suzuki	DF150	150	4-Stroke	All Years	25700-93J00
Suzuki	DF150T	150	4-Stroke	2006 & Up	25700-93J00
Suzuki	DF175	175	4-Stroke	All Years	25700-93J00
Suzuki	DF175T	175	4-Stroke	2006 & Up	25700-93J00
Suzuki	DF200	200	4-Stroke	All Years	25700-93J00
Suzuki	DF200T	200	4-Stroke	2004 & Up	25700-93J00
Suzuki	DF200A	200	4-Stroke	All Years	25700-93J00
Suzuki	DF200AP	200	4-Stroke	All Years	25700-93J00
Suzuki	DF225	225	4-Stroke	All Years	25700-93J00
Suzuki	DF225T	225	4-Stroke	2004 & Up	25700-93J00
Suzuki	DF250	250	4-Stroke	All Years	25700-93J00
Suzuki	DF250T	250	4-Stroke	2004 & Up	25700-93J00

Technical Specs

Product Type: Gearcase Seal Kit
Installation: Lower Unit
Product Dimensions: 7.5" L x 6.0" W x 1.0" H
Weight: 0.5 lbs (0.23 kg)

What’s in the Box

All seals required to disassemble and reseal the gearcase

Installation Notes

Drain the gearcase oil completely.
Carefully remove the lower unit assembly from the outboard's midsection.
Disassemble the gearcase, including the propeller shaft housing and driveshaft bearing carrier, noting the orientation of all parts.
Remove and discard all old seals, gaskets, and O-rings.
Thoroughly clean all sealing surfaces, ensuring they are free of old adhesive, corrosion, and debris.
Lightly lubricate the new seals with marine grease before installation.
Install the new components from the kit into their correct positions.
Reassemble the gearcase, applying sealant where required and torquing all fasteners to the manufacturer's specifications.
Reinstall the lower unit and fill with fresh gear lube. Check for any leaks before operation.

Troubleshooting & FAQ

How do I know if this seal kit fits my Suzuki outboard?

This kit is designed for Suzuki DF150 through DF250 4-stroke models from approximately 2004 to present. Please verify your exact model and year against the compatibility table provided. The OEM part number this kit replaces is 25700-93J00.

What are the signs of a failing lower unit seal?

Common signs include milky or water-contaminated gear oil (which looks like coffee with cream), visible oil leaks around the propeller shaft or driveshaft, or a metallic sheen in the drained oil, which can indicate water intrusion and subsequent gear wear.

How often should lower unit seals be replaced?

It's best practice to inspect the gear lube annually for water. We recommend replacing the seals every 3–5 years as preventative maintenance, or immediately if you notice any signs of leakage or water contamination.

Does this kit include the main driveshaft and propeller shaft seals?

Yes, this is a comprehensive kit containing the necessary seals, O-rings, and gaskets required to fully reseal the lower unit gearcase, including seals for the driveshaft, prop shaft, and shift shaft.

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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