Powerhead Gasket – Fits Mercury/Quicksilver 75-115HP EFI 4-Stroke Outboards (Replaces 8M0005405)
Powerhead Gasket – Fits Mercury/Quicksilver 75-115HP EFI 4-Stroke Outboards (Replaces 8M0005405) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Powerhead Gasket – Fits Mercury/Quicksilver 75-115HP EFI 4-Stroke O...
Product Details
This is a direct replacement Powerhead Gasket – Fits Mercury/Quicksilver 75-115HP EFI 4-Stroke Outboards (Replaces 8M0005405), designed for Mercury Marine 75-115 HP EFI 4-Stroke outboard engines manufactured between 2002–2014. It serves as the adaptor plate gasket, ensuring a proper seal between the powerhead and the adaptor plate.
This part provides a direct interchange for Mercury 8M0005405 and Quicksilver 8M0005405.
- Installs securely between the engine powerhead and adaptor plate.
- Engineered with materials that meet or exceed OEM specifications.
- Ensures a reliable seal to prevent leaks and maintain engine performance.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 8M0005405 |
| Quicksilver | 8M0005405 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury Marine engines, it is critical to verify your engine's serial number falls within the ranges specified in the 'Notes' column to ensure correct fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 75 EFI | 75 | 4-Stroke | 2002–2014 | 8M0005405 | Serial range: 1B366823 THRU 2B094995 |
| Mercury | 80 EFI | 80 | 4-Stroke | 2002–2014 | 8M0005405 | Serial ranges: 0P459572 THRU 2B094995, 1B366823 THRU 2B094995 |
| Mercury | 90 EFI | 90 | 4-Stroke | 2002–2014 | 8M0005405 | Serial range: 1B366823 THRU 2B094995 |
| Mercury | 100 EFI | 100 | 4-Stroke | 2002–2014 | 8M0005405 | Serial ranges: 0P459572 THRU 2B094995, 1B366823 THRU 2B094995 |
| Mercury | 115 EFI | 115 | 4-Stroke | 2002–2014 | 8M0005405 | Serial range: 1B366823 THRU 2B094995 |
Technical Specs
- Product Type
- Powerhead Gasket / Adaptor Plate Gasket
- Installation Location
- Between powerhead and adaptor plate
- Material
- OEM Mercury Marine specification
- Dimensions
- 40 × 28 × 1 cm (approx. 15.7 × 11 × 0.4 in)
- Weight
- 0.23 kg (0.50 lb)
- OEM Part Number
- 8M0005405
- GTIN/UPC
- 0745061721357
What’s in the Box
- 1 × Gasket (8M0005405)
Installation Notes
- Disconnect the battery and follow all standard safety precautions for marine engine service.
- Drain necessary fluids and disconnect fuel lines, electrical connections, and linkages from the powerhead.
- Carefully unbolt and remove the powerhead from the midsection/adaptor plate.
- Remove the old gasket and thoroughly clean both mating surfaces. Ensure they are free of old gasket material, corrosion, and debris.
- Place the new gasket in position, ensuring all bolt holes and passages are correctly aligned.
- Reinstall the powerhead, torquing the bolts to the manufacturer's specified sequence and values.
- Reconnect all lines, connections, and linkages, then refill fluids before testing.
Troubleshooting & FAQ
How do I confirm this gasket fits my specific engine?
Your engine model and horsepower must be listed in the compatibility table. Most importantly, you must verify your engine's serial number falls within the range specified for your model to guarantee fitment.
What are the signs of a failed powerhead gasket?
Common symptoms include engine overheating, loss of compression, water mixing with oil (milky oil), or poor engine performance. A visual inspection may also reveal water or exhaust leaks between the powerhead and adaptor plate.
Can I reuse my old gasket after removing the powerhead?
No. Gaskets are designed for one-time use. They compress to create a seal and will not provide a reliable seal if reused, likely leading to leaks and engine damage.
Is this gasket made of the same material as the OEM part?
This gasket is manufactured to meet or exceed original equipment manufacturer (OEM) specifications for material and performance. While the exact material composition is proprietary, it is designed for durability and a proper seal in marine environments.
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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