Lower Unit Seal Kit 26-16130 8150264 for Mercury Mariner 4 5 6 HP Outboard Gearcase
Lower Unit Seal Kit 26-16130 8150264 for Mercury Mariner 4 5 6 HP Outboard Gearcase
Product Overview
Lower unit seal kit 26-16130 for Mercury and Mariner 4 HP, 5 HP and 6 HP outboards, the gearcase set that replaces 26-16130 with the oil seal, the O ring seal 25-16131, the cotter pin 8150264 and the drain screw gaskets. The oil seal is 15 mm x 28 mm x 10 mm and the O ring is 3.1 mm x 47 mm inside diameter, so both are the small gearcase parts used on these four stroke and two stroke 4 to 6 HP motors.
It fits all models of the 4 HP, 5 HP and 6 HP Mercury and Mariner outboards where the gearcase takes this seal set. Verify the model or serial number if the motor has been rebuilt or is a late production unit, because Mercury changed gearcase seal arrangements across the years.
Water in the gear oil is the reason most of these kits get sold. The oil seal sits behind the prop shaft, the O ring seals the bearing carrier, and a damaged one lets lake or sea water into the gearcase. Gear oil that comes out milky means the damage is already happening, and every trip after that wears the bearings and the gears.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Outboard lower unit seal kit |
| Fits | Mercury and Mariner 4 HP, 5 HP and 6 HP outboards |
| Models | All models using this gearcase seal set |
| Oil Seal Size | 15 mm inside diameter x 28 mm outside diameter x 10 mm |
| O Ring Size | 3.1 mm section x 47 mm inside diameter |
| Replaces | 26-16130, 25-16131, 8150264, 8M0082880, 95200 |
| Net Weight | 22 g including packaging |
| Pack Size | 150 mm x 180 mm x 40 mm |
| Warranty | 3 year |
OEM Cross Reference
| Component | OEM Part Numbers |
|---|---|
| Lower unit seal kit | 26-16130 |
| Oil seal | 26-16130, 369-60111-0 |
| O ring seal | 25-16131, F8-04040002, 345-65015-0 |
Compatible Engines
| Horsepower | Brand | Models | Gearcase |
|---|---|---|---|
| 4 HP | Mercury | All models | Standard lower unit |
| 4 HP | Mariner | All models | Standard lower unit |
| 5 HP | Mercury | All models | Standard lower unit |
| 5 HP | Mariner | All models | Standard lower unit |
| 6 HP | Mercury | All models | Standard lower unit |
| 6 HP | Mariner | All models | Standard lower unit |
What's Included
| Component | Part Number | Qty |
|---|---|---|
| Oil seal, 15 mm x 28 mm x 10 mm | 26-16130 | 1 |
| O ring seal, 3.1 mm x 47 mm inside diameter | 25-16131 | 1 |
| Cotter pin, 3 mm x 22 mm | 8150264, also 951503-0318 | 1 |
| Drain and fill screw gasket | 8M0082880, 95200 | 2 |
| Small ring | 26-830749 | 2 |
| Gearcase housing and bearings | Not included, inspect while apart | 0 |
Signs The Gearcase Is Taking Water
| What You See | What It Means | What To Do |
|---|---|---|
| Gear oil comes out milky | Water past the prop shaft seal | Full seal kit and new gear oil |
| Oil film around the propeller | Oil seal weeping | Seal kit with the new oil seal |
| Whine or rumble from the gearcase | Bearings damaged by water | Seal kit, then inspect the bearings |
| Gear oil drips on the driveway | Drain screw gasket flattened | New gaskets from the kit |
| Prop shaft has side play | Bearing carrier worn | Seal kit, check the carrier and shaft |
| Water in the oil every season | Repeat failure, shaft scored | Check the shaft surface before refitting |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Check the model and serial number against the 4, 5 and 6 HP fitment |
| 2 | Drain the gear oil first and look at it, milky oil means water ingress |
| 3 | Take the prop and the bearing carrier out and keep the shims in order |
| 4 | Press the old oil seal out and clean the carrier bore |
| 5 | Inspect the prop shaft where the seal lip runs, polish or replace if grooved |
| 6 | Fit the new oil seal square and grease the lip before assembly |
| 7 | Fit the new O ring on the carrier and refit with the original shims |
| 8 | Fill with gear oil, fit the new drain gaskets and pressure test before the next trip |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | 3 year |
| Packaging | Sealed retail packaging |
Before You Buy
- Fits Mercury and Mariner 4 HP, 5 HP and 6 HP outboards
- Kit number 26-16130, with O ring seal 25-16131
- Oil seal is 15 mm x 28 mm x 10 mm
- O ring is 3.1 mm section and 47 mm inside diameter
- Includes the cotter pin and two drain screw gaskets
- Gear oil is not included, buy a full gearcase fill
- 30-Day Easy Returns
- Ships from our warehouse with tracking
Couldn't load pickup availability
Boat Owners' Review
Before You Buy
Frequently Asked Questions
What is your refund policy?
We offer a 14-day hassle-free return on all products. Items must be unused and in original packaging. Every XRmarine part is also covered by our 1-year warranty against manufacturing defects. If something is not right, email us at info@xrmarineparts.com — replacement or full refund, your choice.
See our full Refund Policy for complete details.
How does shipping work?
Free international shipping on every order — no minimums. We operate a global warehouse network with a main distribution centre in Asia (10-20 business days). We also hold stock in regional warehouses across the United States, Germany, the United Kingdom, Australia, and Poland (opening soon) — most orders arrive in 1-3 business days within those countries and in 2-8 business days to nearby regions. Tracking included.
See our full Shipping Policy.
How do you keep prices fair?
We cut out the middlemen. XRmarine sources directly from quality manufacturers and sells at honest prices. Same OEM-quality parts, no dealership markup. Every order comes with free shipping, real expert support, and a 1-year warranty.
Learn more on our About Us page.
What payment methods do you accept?
We currently accept PayPal — a fast, secure way to pay online. Credit card payments (Visa, Mastercard, American Express) and Shopify Payments are being set up and will be available soon. We appreciate your patience.