Gasket – Fits Mercury-Mercruiser V6 (Replaces Mercury-Mercruiser 27-42457, OMC 0509252)
Gasket – Fits Mercury-Mercruiser V6 (Replaces Mercury-Mercruiser 27-42457, OMC 0509252) 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
Gasket – Fits Mercury-Mercruiser V6 (Replaces Mercury-Mercruiser 27...
Product Details
This Gasket – Fits Mercury-Mercruiser V6 is engineered for a precise fit on Mercury Marine and MerCruiser MCM GM V-6 engines from 1985 through 1992. It is also designed as a compatible replacement for various OMC V6 models, ensuring a reliable seal for the fuel pump mounting plate.
This part serves as a direct replacement, offering a reliable interchange for Mercury-Mercruiser 27-42457, OMC 0509252, Quicksilver 27-42457, and GLM 31700.
- Installation: Mounts between the engine block and the fuel pump mounting plate.
- Material: Constructed from material resistant to hydrocarbons and the harsh marine environment.
- Package Contents: Includes one gasket for a complete replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury-Mercruiser | 27-42457 |
| OMC | 0509252 |
| Quicksilver | 27-42457 |
| GLM | 31700 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury-Mercruiser Engines: Fits various GM V-6 models from 1983 to 1992, including 175, 185, 205, 4.3L, and 4.3LX variants.
For OMC Engines: Serves as a direct cross-reference for part number 0509252 used in miscellaneous V6 models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury-Mercruiser | 175 (2 BBL.) GM 262 V-6 | 175 | 4-Stroke | 1987 | 27-42457 | |
| Mercury-Mercruiser | 185 (2 BBL.) GM 262 V-6 | 185 | 4-Stroke | 1985–1987 | 27-42457 | |
| Mercury-Mercruiser | 185 (4 BBL.) GM 229 V-6 | 185 | 4-Stroke | 1983–1984 | 27-42457 | |
| Mercury-Mercruiser | 205 (4 BBL.) GM 262 V-6 | 205 | 4-Stroke | 1985–1987 | 27-42457 | |
| Mercury-Mercruiser | 205 (4 BBL.) GM 262 V-6 | 205 | 4-Stroke | 1987 | 27-42457 | |
| Mercury-Mercruiser | 4.3L (2 BBL.) GM 262 V-6 | 4-Stroke | 1988–1992 | 27-42457 | ||
| Mercury-Mercruiser | 4.3LX (4 BBL.) GM 262 V-6 | 4-Stroke | 1988–1992 | 27-42457 | ||
| OMC | V6 (Misc. models) | 0509252 | Direct cross for 27-42457 |
Technical Specs
- Product Type
- Gasket
- Installation
- Fuel Pump Mounting Plate
- Fuel Type
- Gasoline
- Dimensions
- Length: 10.0 in | Width: 10.0 in | Height: 0.4 in
- Weight
- 0.009 kg (0.02 lb)
- Other Technical Attributes
- Made of material resistant to hydrocarbons and marine environment.
What’s in the Box
- 1 x GASKET (27-42457)
Installation Notes
- Disconnect the vessel's battery and follow all safety precautions for working with fuel systems.
- Carefully relieve any pressure from the fuel system according to the manufacturer's service manual.
- Disconnect the fuel lines from the fuel pump, labeling them to ensure correct reassembly.
- Remove the mounting bolts securing the fuel pump and its mounting plate to the engine block.
- Gently remove the pump and plate, then discard the old gasket.
- Thoroughly clean both the engine block surface and the pump plate surface, ensuring they are free of old gasket material and debris.
- Position the new gasket correctly on the mounting surface.
- Re-install the fuel pump and plate, tightening the bolts to the manufacturer's specified torque.
- Reconnect the fuel lines and the battery, then prime the fuel system and check for leaks before starting the engine.
Troubleshooting & FAQ
How do I confirm this gasket fits my specific engine model?
Always check your engine's part manual or existing part number first. Then, compare it against the numbers in our Part Number Matrix and the models listed in the Engine & Model Compatibility table. Verifying against the visual details in the product photos is also a critical step.
What are common signs that my fuel pump gasket is failing?
A failing gasket typically causes a fuel leak around the fuel pump mounting base. You might notice a strong smell of gasoline, visible seepage, poor engine performance, or difficulty starting due to a loss of fuel pressure.
Is this gasket compatible with modern gasoline containing ethanol?
Yes, this gasket is made from modern materials designed to be resistant to the corrosive effects of ethanol-blended fuels (E10, E15), ensuring durability and a long service life.
Can I reuse my old fuel pump gasket after an inspection?
No. Gaskets are single-use components that compress to create a seal. Once compressed and exposed to heat cycles, they lose their ability to form a reliable seal and should always be replaced when the component is removed.
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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