Water Pump Base Gasket – Fits Mercury Marine/MerCruiser (Replaces 27-32438)
Water Pump Base Gasket – Fits Mercury Marine/MerCruiser (Replaces 27-32438) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Base Gasket – Fits Mercury Marine/MerCruiser (Replaces 2...
Product Details
This is a direct replacement Water Pump Base Gasket – Fits Mercury Marine/MerCruiser (Replaces 27-32438). It is designed for a precise fit on a wide range of Mercury Marine and MerCruiser stern drives and outboard motors, including models from the 650 (4 cyl) through 1500 series.
This gasket serves as a direct interchange for Mercury part 27-32438, Sierra 18-2801, and SEI Marine 95-299-02B.
- Installation Method: Direct replacement for the original gasket.
- Material: High-quality composite gasket material designed for marine environments.
- Function: Creates a seal between the water pump base and the gear housing.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 27-32438 |
| Sierra | 18-2801 |
| SEI Marine | 95-299-02B |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | OEM Part No. | Notes |
|---|---|---|---|
| Mercury | 650 (4 CYL.) | 27-32438 | Multiple serial number ranges: 1542745-1765043, 1765044-2119748, 2119749-2309310, 2309311-2803561, 2803562-3293183 |
| Mercury | 700 (6 CYL.) | 27-32438 | Serial range: 1413611-1566239 |
| Mercury | 800 (4 CYL.), 80 (4 CYL.) | 27-32438 | Serial range: 2559001-3493912 |
| Mercury | 850 (6 CYL.) | 27-32438 | Serial range: 1460999-1766823 |
| Mercury | 900 (6 CYL.) | 27-32438 | Serial range: 1766824-1869775 |
| Mercury | 950 (6 CYL.) | 27-32438 | Serial range: 1869776-2318585 |
| Mercury | 1000 | 27-32438 | Serial ranges: 1464949-1768403, 1768404-2318585 |
| Mercury | 1000SS | 27-32438 | Serial range: 2318586-2836018 |
| Mercury | 1100 | 27-32438 | Serial range: 1870204-2314955 |
| Mercury | 1150 | 27-32438 | Serial ranges: 2836019-3525440, 3525441-4855152, 7010763-7112248, 8008665-8051949 |
| Mercury | 1250 | 27-32438 | Serial range: 2314956-2839368 |
| Mercury | 1350 | 27-32438 | Serial range: 2839369-3293233 |
| Mercury | 1400 | 27-32438 | Serial range: 3293234-3502805 |
| Mercury | 1500 | 27-32438 | Serial ranges: 3502806-4865677, 7010533-7112772, 8005615-8052649 |
| Mercury | I 1963 | 27-32438 | Serial range: 1534570-1684187 |
| Mercury | MR/Alpha 1 Drives | 27-32438 | Part of water pump kits: 46-57234A8, 46-96148Q8 |
Technical Specs
- Product Type
- Water Pump Base to Gear Housing Gasket
- Installation
- Direct replacement
- Housing Material
- Gasket material (paper/composite)
- Dimensions
- Height: 6.0 in; Width: 7.5 in; Length: 1.03 in;
- Weight
- 1.6 oz (45.36 g)
- Other Technical Attributes
- Used on water pump assemblies in Mercury Marine/MerCruiser applications
What’s in the Box
- 1 x Gasket, Water Pump Base to Gear Housing (27-32438)
Installation Notes
- Disconnect the battery and ensure the engine is cool. Remove the lower unit (gearcase) from the outboard or stern drive.
- Locate and remove the water pump housing to access the base gasket area.
- Carefully remove the old gasket, ensuring the mating surfaces on the gear housing and water pump base are completely clean of any old material or sealant.
- Place the new gasket into position, ensuring it aligns perfectly with all bolt holes and water passages.
- Reinstall the water pump assembly and lower unit, torquing all fasteners to the manufacturer's specified values in the correct sequence.
Troubleshooting & FAQ
How do I know if this gasket will fit my specific engine model?
The most reliable way to confirm fitment is to match your engine's serial number to the ranges listed in the Engine & Model Compatibility table. You can also cross-reference your existing part number with the ones provided in our Part Number Matrix.
What are the signs of a failing water pump base gasket?
Common signs include engine overheating (due to water pressure loss), visible water leaks around the gearcase seam when running, or a weak "telltale" stream. A damaged gasket can compromise the water pump's efficiency.
How often should this gasket be replaced?
It is best practice to replace this gasket every time you service the water pump impeller, which is typically recommended every 1-2 years or 100-200 hours of use, depending on operating conditions (especially in saltwater).
Do I need to use gasket sealant with this part?
In most applications, this gasket is designed to be installed dry. Applying sealant can sometimes cause the gasket to slip out of place during installation. Always follow your specific engine's service manual for guidance.
What is the difference between this and the OEM gasket?
This part is an aftermarket replacement designed to meet or exceed original equipment manufacturer (OEM) specifications for fit, material, and function. It offers a cost-effective solution without compromising on quality or performance.
Can a bad base gasket cause other damage?
Yes. A leaking gasket can lead to insufficient cooling, potentially causing severe engine damage from overheating. It can also allow water to enter the gearcase, which can lead to catastrophic gear and bearing failure if not addressed.
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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