Gasket – Mercury Marine 40-60HP (Replaces Mercury Marine 27-385011, 27-38501, 27-37724, 27-377424)
Gasket – Mercury Marine 40-60HP (Replaces Mercury Marine 27-385011, 27-38501, 27-37724, 27-377424) 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
Gasket – Mercury Marine 40-60HP (Replaces Mercury Marine 27-385011,...
Product Details
This adaptor plate Gasket for Mercury Marine 40-60HP outboards provides a reliable seal for the exhaust system. It is designed for a precise fit on various 2-stroke Mercury Marine models from the mid-1970s onwards, including 30 JET, 35, 40 (4-Cyl), 45 (4-Cyl), 50 (3-Cyl), and 60 (3-Cyl) engines.
It serves as a direct replacement for Mercury OEM part 27-385011 and interchanges with aftermarket parts including Sierra 18-0879, Mallory 9-60042, and GLM 31400.
- Installs between the adaptor plate and the exhaust extension plate.
- Engineered to meet or exceed OEM specifications for durability and sealing performance.
- Ensures proper sealing of exhaust and water passages.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury Marine | 27-385011 | Current OEM Part Number |
| Mercury Marine | 27-38501 | Superseded by 27-385011 |
| Mercury Marine | 27-37724 | Superseded by 27-385011 |
| Mercury Marine | 27-377424 | Superseded by 27-385011 |
| Sierra | 18-0879 | Aftermarket Interchange |
| Mallory | 9-60042 | Aftermarket Interchange |
| GLM | 31400 | Aftermarket Interchange |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years / Serial Range | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury Marine | 30 JET | 30 | 2-Stroke | 0C159200–0G589999, 9570790 and up | 27-385011 | |
| Mercury Marine | 35 | 35 | 2-Stroke | 9466647 and up, B110789 and up | 27-385011 | |
| Mercury Marine | 40 (4 CYL.) | 40 | 2-Stroke | 0C159200 and up, 9570790 and up | 27-385011 | |
| Mercury Marine | 45 (4 CYL.) | 45 | 2-Stroke | 0A719281 and up, 0B110789 and up, 9466692 and up | 27-385011 | |
| Mercury Marine | 50 (3 CYL.) | 50 | 2-Stroke | 0A721308 and up, 0B122930–0D000749, 9469200–9683054 | 27-385011 | |
| Mercury Marine | 60 (3 CYL.) | 60 | 2-Stroke | 0A721308 and up, 0B122930–0D000749, 9469200–9683054 | 27-385011 |
Technical Specs
- Product Type
- Gasket
- Installation Location
- Adaptor Plate / Exhaust Extension Plate
- Dimensions
- 27.0" L x 17.0" W x 0.5" H (685.8 x 431.8 x 12.7 mm)
- Weight
- 0.16 ounces (approx. 4.5 g)
- Attribute
- Meets or exceeds OEM specifications.
What’s in the Box
- 1x Gasket
Installation Notes
- Ensure the engine is off, cool, and the battery is disconnected before starting.
- Locate the adaptor plate or exhaust extension plate where the gasket is installed.
- Carefully remove any components that obstruct access to the gasket mounting bolts.
- Unbolt and remove the component to access the old gasket.
- Thoroughly clean both mating surfaces. Remove all traces of old gasket material, sealant, and corrosion.
- Position the new gasket, ensuring all holes align perfectly. Do not use sealant unless specified by your engine's service manual.
- Reinstall the plate/component, tightening bolts in the correct sequence and to the manufacturer's recommended torque specifications.
- Reconnect the battery and test for any exhaust or water leaks before operation.
Troubleshooting & FAQ
How do I know if this gasket fits my engine?
This gasket is for specific Mercury Marine 2-stroke outboard models (30-60 HP). The best way to confirm fitment is to match your engine's model and serial number to the compatible ranges listed in our table. Cross-referencing the OEM part number (27-385011) is also a reliable method.
What are the signs of a failing adaptor plate gasket?
Symptoms of a bad gasket include engine overheating, water in the cylinders, a noticeable drop in performance, or visible water and/or exhaust leaking from the seam between the powerhead and driveshaft housing.
Do I need to use sealant with this gasket?
In most cases, this gasket is designed to be installed dry. However, you should always consult your engine's official service manual for specific instructions, as some models may require a light application of a specific sealant.
When should this gasket be replaced?
This gasket should be replaced any time the component it seals is removed for service. It should also be replaced immediately if you diagnose a leak or other signs of failure.
What is the difference between part 27-385011 and older part numbers?
Part number 27-385011 is the latest revision from Mercury Marine, which supersedes older numbers like 27-38501 and 27-37724. This aftermarket part is manufactured to serve as a direct replacement for all listed OEM and aftermarket cross-reference numbers.
Is this a genuine OEM part?
This listing is for a high-quality aftermarket replacement, not an OEM part. It is engineered to meet or exceed original equipment manufacturer specifications for fit, form, and function, offering comparable performance at a better value.
What are your shipping speeds & costs?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If any issues arise, contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. Please see our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchasing. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is highly recommended for safety and optimal 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 quality control.
Payment & Security
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