Propeller Shaft Oil Seal – Fits Mercury Outboard 30–150 HP (Replaces 26-70081, 26-8M0205729)
Propeller Shaft Oil Seal – Fits Mercury Outboard 30–150 HP (Replaces 26-70081, 26-8M0205729) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Propeller Shaft Oil Seal – Fits Mercury Outboard 30–150 HP (Replace...
Propeller Shaft Oil Seal – Fits Mercury Outboard 30–150 HP (Replaces 26-70081, 26-8M0205729) is backordered and will ship as soon as it is back in stock.
Product Details
This high-quality Propeller Shaft Oil Seal is engineered for the lower unit gear housing of various Mercury, Mariner, Force, and Honda outboard engines. It provides a robust replacement for models ranging from 30 HP to 150 HP, including numerous 2-stroke and 4-stroke applications across several decades of production, as well as Honda BF75 and BF90 series engines from 1997–1998.
It serves as a direct replacement for multiple OEM and aftermarket parts, including Mercury 26-70081 and 26-8M0205729, Honda 91255-ZW1-003, Sierra 18-2053, and GLM 85530.
- Installs in the lower unit gear housing to seal the propeller shaft.
- Constructed from durable, saltwater-resistant nitrile rubber.
- Features a dual-lip design for primary sealing and dust protection.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury Marine | 26-70081 |
| Mercury Marine | 26-8M0205729 |
| Honda Marine | 91255-ZW1-003 |
| Force/US Marine | 26-70081 |
| Sierra | 18-2053 |
| GLM | 85530 |
| Mallory | 9-76115 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits a wide range of Mercury and Mariner outboards (2-stroke and 4-stroke) from 30 HP to 225 HP, including DFI, EFI, and Bigfoot models.
Compatible with select Force 2-stroke outboards from 1995–1999.
Designed for specific Honda 4-stroke models from 1997–1998.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | V-225 | 225 | 2-Stroke | 26-70081 | Gear Housing (Prop Shaft) | |
| Mercury | V-200 | 200 | 2-Stroke | 1978–1988 | 26-70081 | Without Driveshaft Nut |
| Mercury | V-150/V-1500 | 150 | 2-Stroke | 1978–1985 | 26-70081 | V-6 Series incl. XR-2, Marathon, Magnum, Work models |
| Mercury | Pro XS | 115 | 2-Stroke | 26-70081 | 3-Cylinder 1.5L | |
| Mercury/Mariner | 4-Stroke EFI | 115 | 4-Stroke | 26-70081 | 2.07:1 & 2.33:1 Gear Ratios | |
| Mercury/Mariner | 4-Stroke EFI | 75-100 | 4-Stroke | 26-70081 | Multiple gear ratios | |
| Mercury/Mariner | DFI | 75-125 | 2-Stroke | 26-70081 | 3-Cylinder 1.5L | |
| Mercury/Mariner | 3-Cylinder | 70-90 | 2-Stroke | 26-70081 | Including Jet models | |
| Mercury/Mariner | 4-Cylinder | 75-125 | 2-Stroke | 26-70081 | Including 80 Jet models | |
| Mercury | Bigfoot | 40-60 | 4-Stroke | 26-70081 | 3-Cylinder and 4-Cylinder models | |
| Mercury/Mariner | Standard | 50-60 | 2-Stroke | 26-70081 | Includes Jet 40-45 variants | |
| Mercury | Merc | 80-115 | 2-Stroke | 26-70081 | Gear Housing (Propeller Shaft) | |
| Force | Standard | 90 | 2-Stroke | 1995–1999 | 26-70081 | Multiple clutch types |
| Force | Standard | 120 | 2-Stroke | 1995–1999 | 26-70081 | Multiple clutch types |
| Force | Standard | 75 | 2-Stroke | 1999 | 26-70081 | |
| Honda | BF75AT | 75 | 4-Stroke | 1997–1998 | 91255-ZW1-003 | LHTA, LRTA & XRTA variants |
| Honda | BF90AT | 90 | 4-Stroke | 1997–1998 | 91255-ZW1-003 | LHTA, LRTA & XRTA variants |
Technical Specs
- Product Type
- Propeller Shaft Oil Seal
- Installation Location
- Lower Unit / Gear Housing
- Housing Material
- Nitrile Rubber
- Dimensions
- OD: 45mm (1.76"), ID: 30mm (1.185"), Width: 9.1mm (0.35")
- Temperature Range
- -30°C to 120°C (-22°F to 248°F)
- Construction
- Dual-lip design with primary sealing and dust protection
- Features
- Saltwater, oil, and temperature resistant
What’s in the Box
- 1 or 2 x Propeller Shaft Oil Seal (Replaces 26-70081/26-8M0205729)
- Note: Package quantity varies by seller. Some listings include a single seal, while others include a two-pack. Please verify the quantity before ordering.
Installation Notes
- Position the outboard securely on an engine stand or with the lower unit tilted up. Place a drain pan under the gearcase.
- Remove the lower gearcase drain and vent screws and allow all gear lube to drain completely.
- Remove the propeller nut and slide the propeller, thrust washer, and spacers off the shaft.
- Unbolt and carefully remove the bearing carrier assembly from the gearcase. The propeller shaft will come out with it.
- Using a seal puller or flat-head screwdriver, carefully pry the old oil seals out of the bearing carrier. Avoid scratching the metal housing.
- Thoroughly clean the seal housing area inside the bearing carrier to remove any old sealant or corrosion.
- Lightly coat the outer edge of the new seals and the inner surface of the housing with marine grease.
- Using a seal driver or a socket with a matching outside diameter, press the new seals squarely into the carrier until fully seated. Ensure the sealing lips face the correct direction (typically, sealing lips face the oil you are containing).
- Lubricate the sealing lips and reinstall the propeller shaft and bearing carrier assembly.
- Reinstall the propeller, hardware, and gearcase screws. Refill the lower unit with fresh, high-quality marine gear lube according to your engine's manual.
Troubleshooting & FAQ
How do I confirm this seal will fit my specific engine?
First, check for your engine's model, HP, and year in the compatibility table. Second, it is critical to compare the listed dimensions (OD: 45mm, ID: 30mm, Width: 9.1mm) against your old part before ordering. If the numbers or appearance differ, do not purchase.
What are the signs of a failing propeller shaft seal?
The most common indicators are a visible gear lube leak from the propeller area or finding milky, grey, or chunky gear lube when you drain the lower unit. This "milky" appearance signifies water has mixed with the oil, which can cause catastrophic gear failure if not addressed.
How often should this seal be replaced?
It is recommended to inspect seals during any regular lower unit service (like a water pump impeller change). Proactively replace them every 3-5 years or 300 operating hours to prevent water intrusion. Always replace the seal if you see any signs of leaking.
Why do some sellers offer one seal and others offer two?
Many gearcase designs use two of these seals installed back-to-back in the bearing carrier—one to keep gear oil in, and one to keep water out. Some sellers provide two seals for a complete replacement, while others sell them individually. Check the listing details to confirm the quantity provided.
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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