Water Pump Gasket – Fits Mercury Outboards & MerCruiser Sterndrives (Replaces 27-856081)
Water Pump Gasket – Fits Mercury Outboards & MerCruiser Sterndrives (Replaces 27-856081) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Gasket – Fits Mercury Outboards & MerCruiser Sterndr...
Product Details
This Water Pump Gasket – Fits Mercury Outboards & MerCruiser Sterndrives (Replaces 27-856081) is designed for the water pump housing assembly on a wide range of Mercury outboard engines from V-115 to V-200 models, as well as MerCruiser Alpha One sterndrives (1983-1990). It provides a reliable seal for the lower unit gear case.
This part is a direct replacement for Mercury OEM part numbers 27-856081 and its successor, 8M0090319, as well as Sierra aftermarket part 18-2914.
- Installs as a direct-fit replacement.
- Designed for the lower unit / gear case cooling system.
- Includes one gasket.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By |
|---|---|---|
| Mercury | 27-856081 | 8M0090319 |
| Sierra | 18-2914 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury Outboard Engines:
| Brand | Model | Rated HP | OEM Part No. | Notes |
|---|---|---|---|---|
| Mercury | 90 (6 CYL.) | 90 | 27-856081 | Used on serial #6436123 & Up |
| Mercury | 90 (6 CYL.) | 90 | 27-856081 | Used on serial #7208848 & Up |
| Mercury | 115 (6 CYL.) | 115 | 27-856081 | Used on serial #6436123 & Up |
| Mercury | 115 (6 CYL.) | 115 | 27-856081 | Used on serial #7208848 & Up |
| Mercury | V-115 DFI (2.5L) | 115 | 27-856081 | Used on serial #0G960500 THRU 0T178499 |
| Mercury | V-135 | 135 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-135 DFI (2.5L) | 135 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-140 (INTERNATIONAL) | 140 | 27-856081 | Used on serial #0T178500 THRU 1B226999 |
| Mercury | 140 JET | 140 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-150 | 150 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-150 (EFI) | 150 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-150 DFI (2.5L) | 150 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-150 EFI (2.5L) | 150 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-150 Magnum | 150 | 27-856081 | Used on serial #5600162 THRU 0A904645 |
| Mercury | V-150 Marathon | 150 | 27-856081 | Used on serial #5600162 THRU 0A904645 |
| Mercury | V-150 Work | 150 | 27-856081 | Used on serial #4868998 THRU 0A904645 |
| Mercury | V-1500 | 150 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-150-XR-2 | 150 | 27-856081 | Used on serial #4868998 THRU 0A904645 |
| Mercury | V-150XRI (EFI) | 150 | 27-856081 | Used on serial #0D082000 THRU 0G303045 |
| Mercury | 150 EFI PRO MAX/SUPER MAG | 150 | 27-856081 | Used on serial #0D935000 THRU 0G610049 |
| Mercury | 150/200 EFI PRO MAX/SUPER MAG | 150/200 | 27-856081 | Used on serial #0G610050 THRU 0G856999 |
| Mercury | 150 Pro XS (2.5L) | 150 | 27-856081 | Used on serial #1B690542 & Up |
| Mercury | V-175 | 175 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-175 (EFI) | 175 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-175 (SKI) | 175 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-175 DFI (2.5L) | 175 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-175 EFI (2.5L) | 175 | 27-856081 | Used on serial #0T409000 THRU 0T800999 |
| Mercury | V-175XRI (EFI) | 175 | 27-856081 | Used on multiple serial ranges |
| Mercury | 175 PROXS (2.5L) | 175 | 27-856081 | Used on serial #1B516339 & Up |
| Mercury | V-200 | 200 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-200 (EFI) | 200 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-200 (2.5L) 1991 ONLY | 200 | 27-856081 | Used on serial #0C291520 THRU 0D081999 |
| Mercury | V-200 EFI (2.5L) | 200 | 27-856081 | Used on multiple serial ranges |
| Mercury | V-200XRI (EFI) | 200 | 27-856081 | Used on multiple serial ranges |
| Mercury | 200 EFI PRO MAX/SUPER MAG | 200 | 27-856081 | Used on serial #0D935000 THRU 0G610079 |
For Mercury MAGNUM/XR/JET Models:
| Brand | Model | OEM Part No. | Notes |
|---|---|---|---|
| Mercury | MAGNUM II | 27-856081 | Used on multiple serial ranges |
| Mercury | MAGNUM III | 27-856081 | Used on multiple serial ranges |
| Mercury | XR-4 | 27-856081 | Used on multiple serial ranges |
| Mercury | XR-6 | 27-856081 | Used on multiple serial ranges |
| Mercury | 105 JET | 27-856081 | Used on multiple serial ranges |
| Mercury | 110 Jet (2.5L) | 27-856081 | Used on serial #1B690542 & Up |
For MerCruiser Sterndrives:
| Brand | Model | Years | OEM Part No. | Notes |
|---|---|---|---|---|
| MerCruiser | R/MR/ALPHA ONE (Sterndrive) | 1983–1990 | 27-856081 | Used on serial #6225577 THRU 0F386995 |
| MerCruiser | R/MR/ALPHA ONE (Transom Assembly) | 1983–1990 | 27-856081 | Used on serial #6216687 THRU 0F386995 |
Technical Specs
- Product Type
- Water Pump Housing Gasket
- Installation
- Direct Fit
- Material
- Composite/Paper
- Application
- Lower Unit/Gear Case
- Dimensions
- 6.0" H x 7.5" W x 1.06" L
- OEM Replacement
- Yes
- OEM Supersession
- Original 27-856081 superseded by 8M0090319
What’s in the Box
- 1 x Gasket (Replaces 27-856081/8M0090319)
Installation Notes
- Disconnect the battery and ensure the engine is off and cool.
- Place the outboard gearshift in the forward position.
- Remove the lower unit (gear case) from the outboard by unbolting it.
- Remove the water pump housing cover and the old impeller.
- Clean the mating surfaces of the housing and wear plate, removing any old gasket material.
- Install the new gasket, followed by the new impeller and housing.
- Apply a light coat of marine grease to the new gaskets and O-rings.
- Reassemble the water pump housing and torque bolts to manufacturer specifications.
- Reinstall the lower unit, ensuring the driveshaft and water tube align correctly.
- Test the engine using a water supply (flushing muffs) to check for proper cooling system operation and leaks.
Troubleshooting & FAQ
How do I know if this gasket will fit my specific Mercury engine?
The best method is to consult the compatibility tables on this page. Locate your engine model, horsepower, and serial number range to verify a match. This gasket is a direct cross-reference for OEM part number 27-856081.
What are the signs of a failing water pump gasket?
Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "telltale" outlet, steam from the exhaust, or visible water leaks around the gear case parting line.
How often should this gasket be replaced?
It is best practice to replace the water pump gasket whenever you service the water pump impeller. The recommended service interval is typically every 1 to 2 years or 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).
Is this gasket made from the same material as the OEM part?
This aftermarket gasket is manufactured from a high-quality composite/paper material engineered to meet or exceed original equipment manufacturer (OEM) specifications for sealing, durability, and heat resistance in a marine environment.
Can I reuse my old gasket if it looks okay?
No. Gaskets are single-use components that compress and conform to surface imperfections to create a seal. Reusing an old gasket significantly increases the risk of leaks and subsequent engine damage from overheating.
What is the difference between an OEM and an aftermarket part?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. The part is manufactured in an ISO 9002 facility and batch-inspected for quality and consistency.
What are the shipping speed and cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout if they are available for your location.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for items that are unused and 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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