Front Cover Mount Gasket – Fits Mercury/MerCruiser 454/502 Mag MPI, 500, 525SC, 600SC, 7.4L/LX & 8.2L Engines (Replaces 27-850456)
Front Cover Mount Gasket – Fits Mercury/MerCruiser 454/502 Mag MPI, 500, 525SC, 600SC, 7.4L/LX & 8.2L Engines (Replaces 27-850456) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Free standard shipping on all orders under 1 KG
Front Cover Mount Gasket – Fits Mercury/MerCruiser 454/502 Mag MPI,...
Product Details
This high-quality Front Cover Mount Gasket provides a reliable seal for the front engine cover on various Mercury Marine and MerCruiser 454 CID (7.4L) and 502 CID (8.2L) V8 engines manufactured from 1996 to 2006 and beyond. It is designed for models including Mag MPI, 500 EFI, 525SC, 600SC, 7.4L/LX, and 8.2L.
This part is a direct replacement for Mercury, Quicksilver, and Brunswick part number 27-850456.
- Engineered for a direct-fit installation.
- Made from durable silicone to withstand demanding marine conditions.
- Designed for use with gasoline-fueled engines.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 27-850456 |
| Quicksilver | 27-850456 |
| Brunswick | 27-850456 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This gasket fits a wide range of MerCruiser big-block engines. Please verify your specific model and year before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| MerCruiser | 454 MAG MPI HORIZON (GEN. VI) | 4-Stroke | 1996–2000 | 27-850456 | |
| MerCruiser | 7.4L MIE (LH) GEN. VI | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 7.4L TBI MIE (LH) GEN. VI | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 7.4L MPI MIE (L29) GEN. VI | 4-Stroke | 1998–2000 | 27-850456 | |
| MerCruiser | 7.4L BRAVO (GEN. VI) | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 7.4L BRAVO (MPI)(GEN. VI) | 4-Stroke | 1998–2000 | 27-850456 | |
| MerCruiser | 7.4LX BRAVO (MPI)(GEN. VI) | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 7.4LX BRAVO (TBI)(GEN. VI) | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 454 MAG. BRAVO (GEN. V) | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 454 MAG. BRAVO MPI (GEN VI) | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 454 MAG MPI BRAVO (GEN VI) | 4-Stroke | 1998 | 27-850456 | |
| MerCruiser | 454 MAG. MPI (SKI) GEN. VI | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 8.2L MIE MPI (GEN. VI) | 4-Stroke | 1996+ | 27-850456 | |
| MerCruiser | 8.2L MIE MPI (LH) GEN. VI | 4-Stroke | 1996–1997 | 27-850456 | |
| MerCruiser | 500 (GEN. VI) | 500 | 4-Stroke | 1997–1998 | 27-850456 |
| MerCruiser | 500 (GEN. +) | 500 | 4-Stroke | 1999+ | 27-850456 |
| MerCruiser | 500 EFI | 500 | 4-Stroke | 27-850456 | |
| MerCruiser | 525 EFI | 525 | 4-Stroke | 27-850456 | |
| MerCruiser | 525 SC - Gen VI | 525 | 4-Stroke | 27-850456 | |
| MerCruiser | 540 | 540 | 4-Stroke | 27-850456 | |
| MerCruiser | 565 EFI | 565 | 4-Stroke | 27-850456 | |
| MerCruiser | 575 SCi | 575 | 4-Stroke | 27-850456 | |
| MerCruiser | 600 SC Bobtail | 600 | 4-Stroke | 1998+ | 27-850456 |
| MerCruiser | 600 SCi | 600 | 4-Stroke | 27-850456 | |
| MerCruiser | 662 SCi | 662 | 4-Stroke | 27-850456 | |
| MerCruiser | 700 SCi | 700 | 4-Stroke | 27-850456 | |
| MerCruiser | 502 MAG. MPI (GEN VI) | 4-Stroke | 1996 | 27-850456 | |
| MerCruiser | 502 MAG MPI BRAVO (GEN VI) | 4-Stroke | 1998 | 27-850456 |
Technical Specs
- Product Type
- Front Cover Mount Gasket
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Housing Material
- Silicone
- Product Dimensions
- 21.5" L x 11.3" W x 0.5" H
What’s in the Box
- 1 x Gasket, Front Cover Mount (27-850456)
Installation Notes
- Disconnect the boat's battery and drain the engine cooling system completely.
- Remove any brackets, belts, pulleys, or accessories that obstruct access to the front engine cover.
- Carefully unbolt and remove the front cover, taking note of bolt lengths and locations.
- Remove the old gasket and use a plastic scraper to thoroughly clean any residual material from both mating surfaces.
- Ensure both the engine block and cover surfaces are clean, dry, and free of oil or debris.
- Carefully position the new gasket onto the engine block, aligning it with the bolt holes.
- Reinstall the front cover, hand-tightening bolts initially.
- Following the manufacturer's service manual, tighten the cover bolts in the specified sequence and to the correct torque values.
- Reinstall all components removed in step 2.
- Refill the engine cooling system with the appropriate coolant.
- Reconnect the battery, start the engine, and carefully inspect for any signs of oil or coolant leaks around the cover.
Troubleshooting & FAQ
How do I know if my front cover gasket is failing?
Common signs of a failing front cover gasket include visible oil or coolant leaks from the front of the engine, particularly around the timing cover. You might also notice unexplained drops in oil or coolant levels, or in severe cases, engine overheating.
Is any sealant required with this gasket?
This silicone gasket is designed to be installed dry on clean surfaces. However, always consult your specific engine's service manual, as some applications may recommend a small amount of sealant at joint corners (e.g., where the oil pan meets the block).
What engines does this gasket fit?
It's designed for a wide range of MerCruiser 454 (7.4L) and 502 (8.2L) big-block V8 engines from approximately 1996 through 2006 and newer, including Gen V, Gen VI, MPI, EFI, and SC models. Please refer to our detailed compatibility table to confirm your specific engine.
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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