Cylinder Head Gasket – Fits Tohatsu/Mercury/Mariner 2–3.5HP 2-Stroke (Replaces 309-01005-2)
Cylinder Head Gasket – Fits Tohatsu/Mercury/Mariner 2–3.5HP 2-Stroke (Replaces 309-01005-2) 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
Cylinder Head Gasket – Fits Tohatsu/Mercury/Mariner 2–3.5HP 2-Strok...
Product Details
This aftermarket Cylinder Head Gasket is engineered for a precise fit on Tohatsu, Mercury, and Mariner 2HP to 3.5HP 2-stroke outboard engines manufactured up to 2006. It ensures a reliable seal between the cylinder head and the engine block, preventing combustion gas leaks and coolant or oil mixing.
It serves as a direct replacement for Tohatsu part number 309-01005-2 and Mercury/Mariner equivalents 27-95299001 and 27-95299.
- Designed for direct, hassle-free installation.
- Constructed from materials resistant to heat, pressure, and chemical corrosion.
- Includes one cylinder head gasket per package.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Tohatsu | 309-01005-2 |
| Mercury/Mariner | 27-95299001 |
| Mercury/Mariner | 27-95299 |
Engine & Model Compatibility
Confirm your engine model and year in the tables below to ensure proper fitment.
For Tohatsu Engines: This gasket fits 2-stroke models from 2HP to 3.5HP up to the 2006 model year.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Tohatsu | M2.5A/B | 2.5 | 2-Stroke | Up to 2006 | 309-01005-2 |
| Tohatsu | M3.5A/B | 3.5 | 2-Stroke | Up to 2006 | 309-01005-2 |
| Tohatsu | M2A/B | 2 | 2-Stroke | Up to 2006 | 309-01005-2 |
| Tohatsu | M3A/B | 3 | 2-Stroke | Up to 2006 | 309-01005-2 |
For Mercury/Mariner Engines: This part is compatible with 2-stroke models from 2HP to 3.3HP up to the 2006 model year, replacing part numbers 27-95299001 and 27-95299.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Mercury | 2M | 2 | 2-Stroke | Up to 2006 | 27-95299001/27-95299 |
| Mercury | 2.5M | 2.5 | 2-Stroke | Up to 2006 | 27-95299001/27-95299 |
| Mercury | 3.3M | 3.3 | 2-Stroke | Up to 2006 | 27-95299001/27-95299 |
| Mariner | 2M | 2 | 2-Stroke | Up to 2006 | 27-95299001/27-95299 |
| Mariner | 2.5M | 2.5 | 2-Stroke | Up to 2006 | 27-95299001/27-95299 |
| Mariner | 3.3M | 3.3 | 2-Stroke | Up to 2006 | 27-95299001/27-95299 |
Technical Specs
- Product Type
- Cylinder Head Gasket
- Installation
- Direct replacement
- Fuel Type
- Gasoline (Petrol)
- Material
- Heat, pressure, and chemical corrosion resistant
- Dimensions
- 15.0cm x 10.0cm x 0.3cm
- Warranty
- 1 year (based on aftermarket replacements)
- Other Technical Attributes
- Engineered to meet or exceed OEM specifications
What’s in the Box
- 1 x Cylinder Head Gasket (309-01005-2/27-95299001/27-95299)
Installation Notes
- Disconnect the battery and ensure the engine is cool.
- Drain the engine coolant completely.
- Remove the spark plug wire and any components obstructing the cylinder head.
- Loosen and remove the cylinder head bolts in the sequence recommended by the manufacturer.
- Carefully lift the cylinder head off the engine block. Avoid using pry tools that could damage the mating surfaces.
- Remove the old head gasket and thoroughly clean both the cylinder head and engine block surfaces of any residue.
- Position the new gasket correctly on the engine block, ensuring any alignment dowels are in place.
- Reinstall the cylinder head and torque the bolts to the manufacturer's specified values and sequence.
- Reassemble all other components, refill the coolant, and reconnect the battery.
- Start the engine and check for leaks.
Troubleshooting & FAQ
How do I know this gasket will fit my engine?
Verify your engine's brand, model, horsepower, and year against the comprehensive compatibility tables provided on this page. If your model is listed, the part is a confirmed fit.
What are the signs of a failed cylinder head gasket?
Common symptoms include engine overheating, a loss of power, white smoke from the exhaust (burning coolant), milky or foamy engine oil, and unexplained coolant loss. If you notice these signs, inspect your gasket immediately.
Is any sealant required during installation?
Most modern head gaskets are designed to be installed dry and do not require any additional sealant. Applying sealant can interfere with the gasket's ability to create a proper seal. Always follow the engine manufacturer's service manual for specific guidance.
How is an aftermarket gasket different from an OEM one?
This is an aftermarket part, meaning it is not sourced from the original engine manufacturer. It has been engineered to meet or exceed OEM specifications for fit, material quality, and performance, offering a cost-effective alternative without compromising reliability.
What is your shipping speed and cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most regions. Expedited shipping options, where available, will be displayed at checkout.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window if the part is unused and in its original condition. Refer to our policy page or contact us for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an OEM component.
- Professional installation is recommended for safety and optimal performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — Enjoy free standard delivery to most regions, with parts typically arriving in 5–15 days.
- Manufacturer-Direct Value — We offer fair pricing by eliminating middlemen, without compromising on materials or quality control.
Payment & Security
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