Cylinder Head Gasket – Fits Mercury/Mariner 135-150 HP V6 2.0L (Replaces 27-96542-1)

$38.99 $62.00

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Cylinder Head Gasket – Fits Mercury/Mariner 135-150 HP V6 2.0L (Replaces 27-96542-1) is backordered and will ship as soon as it is back in stock.

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Product Details

This Cylinder Head Gasket – Fits Mercury/Mariner 135–150 HP V6 2.0L (Replaces 27-96542-1) is an aftermarket replacement for Mercury/Mariner 135–150 HP 2.0L V6 loopcharged outboard engines manufactured between 1976 and 1990.

It serves as a direct cross-reference for Mercury/Mariner part numbers 27-96542-1 and 27-96281T01, as well as Sierra 18-3863 and WSM 505-36.

Installs directly between the cylinder head and the engine block.
Constructed from a durable composite/metal blend to ensure a secure seal in marine environments.
Engineered for use with engines featuring 3.125" (79.38 mm) diameter pistons.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket brands.

Brand	Part Number
Mercury/Mariner	27-96542-1
Mercury/Mariner	27-96281T01
Sierra	18-3863
WSM	505-36

Engine & Model Compatibility

Confirm your engine model and year in the table below to ensure accurate fitment.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	V-135	135	2-Stroke	1986–1988	27-96542-1	Serial Range: 0A904646-0C239552
Mercury/Mariner	135 HP	135	2-Stroke	1976–1990	27-96542-1/27-96281T01	2.0L V6 Loopcharged
Mercury/Mariner	150 HP	150	2-Stroke	1976–1990	27-96542-1/27-96281T01	2.0L V6 Loopcharged
Mercury	150 XR-2 Marathon Magnum	150	2-Stroke	1978–1985	27-96542-1	2.0L V6

Technical Specs

Product Type: Cylinder Head Gasket
Installation: Between cylinder head and block
Fuel Type: Gasoline
Housing Material: Composite/Metal
Dimensions: 16.5" L x 6.0" W x 0.13" H
Fitting Type: Direct fit
Other Technical Attributes: For use with 3.125" (79.38 mm) diameter pistons

What’s in the Box

1 x Head Gasket (Replaces 27-96542-1 / 27-96281T01)

Installation Notes

Ensure the engine is completely cool and disconnect the battery terminals for safety.
Drain the engine's cooling system.
Remove the cylinder head cover and any other components obstructing access to the head bolts.
Loosen and remove the head bolts in the sequence specified by the manufacturer's service manual to prevent head warpage.
Carefully lift the cylinder head off the engine block. Remove the old gasket and thoroughly clean both mating surfaces of any old gasket material or residue.
Position the new head gasket correctly onto the engine block, ensuring all holes align perfectly. Do not use sealant unless explicitly required by the service manual.
Carefully place the cylinder head back onto the block and install new head bolts. Torque the bolts to the manufacturer-specified values in the correct pattern.
Reassemble all previously removed components, refill the cooling system, and reconnect the battery. Start the engine and carefully check for any leaks.

Troubleshooting & FAQ

How can I tell if my head gasket is failing?

Common signs of a blown head gasket include engine overheating, a noticeable loss of power, white smoke from the exhaust, or a milky, frothy appearance in the engine oil, which indicates coolant contamination.

Is this gasket compatible with both 2-stroke and 4-stroke engines?

This gasket is specifically designed for the 2-stroke V6 models listed in the compatibility table. It is not suitable for 4-stroke engines.

Does this gasket require any additional sealant during installation?

This gasket is designed for a dry-fit installation. Applying sealants is generally not recommended as it can interfere with proper sealing unless your engine's official service manual explicitly states otherwise.

What causes a head gasket to fail?

Head gasket failure is most often caused by engine overheating. Other causes can include improper installation, incorrect bolt torque, or engine detonation (knocking).

Is this a single gasket or a pair?

This listing is for a single head gasket. For V6 engines, two gaskets are required to service both cylinder banks. Please adjust the quantity as needed.

What is the difference between this aftermarket part and an OEM one?

This listing is an aftermarket replacement (not OEM). It has been built to OEM-level specifications with comparable materials. All our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.

How fast is shipping?

We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free to most locations, and expedited options will appear at checkout if available for your region.

What is your warranty and return policy?

This product 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, provided the item 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 purchasing. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement part, not an OEM component. Brand names and part numbers are used for reference purposes only.
Professional installation is highly recommended for safety and to ensure optimal performance. Incorrect installation can lead to engine damage.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world reliability.
Fast Global Fulfillment — We offer free standard delivery to most regions with an average transit time of 5–15 days.
Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.

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