Power Head Gasket Kit – Fits Mercury/Mariner Outboard 6/8/9.9/10/15 HP (Replaces 27-42364A92, 42364A92)
Power Head Gasket Kit – Fits Mercury/Mariner Outboard 6/8/9.9/10/15 HP (Replaces 27-42364A92, 42364A92) 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
Power Head Gasket Kit – Fits Mercury/Mariner Outboard 6/8/9.9/10/15...
Product Details
This Power Head Gasket Kit is designed for Mercury and Mariner 6–15 HP, 2-stroke, 2-cylinder outboard motors. It provides a reliable seal for the engine's power head assembly, ensuring optimal performance and preventing leaks.
It serves as a direct replacement for Mercury OEM part numbers 27-42364A92, 27-42364A91, 42364A92, 42364A91, and 42364A86.
- Engineered as a direct-fit replacement for specified models.
- Designed for 2-stroke, 2-cylinder gasoline outboard engines.
- Meets OEM specifications for materials and performance.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 27-42364A92 |
| Mercury | 27-42364A91 |
| Mercury | 42364A92 |
| Mercury | 42364A91 |
| Mercury | 42364A86 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is verified to fit the following Mercury and Mariner outboard models. Please check your specific engine to ensure compatibility.
| Brand | Model | Rated HP | Stroke |
|---|---|---|---|
| Mercury | Outboard | 6 | 2-Stroke |
| Mercury | Outboard | 8 | 2-Stroke |
| Mercury | Outboard | 9.9 | 2-Stroke |
| Mercury | Outboard | 10 | 2-Stroke |
| Mercury | Outboard | 13.5 | 2-Stroke |
| Mercury | Outboard | 15 | 2-Stroke |
| Mercury | Sailmate | 9.9 | 2-Stroke |
| Mercury | Sailpower | 15 | 2-Stroke |
| Mercury | XR-10 | 10 | 2-Stroke |
| Mercury | Magnum | 10 | 2-Stroke |
| Mercury | Sea Pro | 10 | 2-Stroke |
| Mercury | Marathon | 10 | 2-Stroke |
| Mercury | Sea Pro | 15 | 2-Stroke |
| Mercury | Marathon | 15 | 2-Stroke |
| Mercury | Viking | 10 | 2-Stroke |
Technical Specs
- Product Type
- Power Head Gasket Kit
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Dimensions
- 4.0" × 15.0" × 21.0"
- Weight
- 0.2kg (0.44 lb)
- Other Technical Attributes
- For 2-stroke, 2-cylinder engines
What’s in the Box
- Gasket Set (Replaces 27-42364A92)
Installation Notes
- Disconnect the battery and ensure the engine is cool.
- Disassemble the engine components carefully to access the old power head gaskets. Keep all hardware organized.
- Thoroughly clean all mating surfaces to remove any old gasket material, sealant, oil, or debris. A clean, smooth surface is essential for a proper seal.
- Compare the new gaskets with the old ones to confirm correct fitment.
- Install the new gaskets. Do not use any sealant unless specified by the engine's service manual.
- Reassemble the power head components, tightening bolts to the manufacturer's recommended torque specifications and in the correct sequence.
- After reassembly, reconnect the battery, start the engine, and check for any leaks around the newly sealed areas.
Troubleshooting & FAQ
How do I know if my power head gasket is failing?
Common signs of a blown or failing power head gasket include loss of compression in one or more cylinders, water in the cylinders, milky or discolored oil, and engine overheating. A compression test is a reliable way to diagnose the issue.
Are any special tools required for this installation?
Standard mechanic's tools are typically sufficient. However, a torque wrench is highly recommended to ensure bolts are tightened to the correct OEM specifications, preventing leaks and damage.
Can I reuse my old bolts with this new gasket set?
It is generally recommended to use new or clean, inspected hardware. If the original bolts are stretched, corroded, or damaged, they should be replaced to ensure proper clamping force and a reliable seal.
What is the recommended replacement interval for these gaskets?
Power head gaskets do not have a fixed replacement interval. They should be replaced whenever the power head is serviced or disassembled, or if signs of a gasket failure are present.
Does this kit include every gasket for the engine?
This is a power head gasket set. It includes the necessary gaskets for rebuilding the engine's cylinder head assembly. It may not include every gasket for the entire motor (e.g., lower unit or carburetor gaskets).
My engine model is listed, but the year is not. Will it fit?
This kit is designed to fit a wide range of model years. The best practice is to always compare the photos and listed part numbers to your existing part before ordering to guarantee compatibility.
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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