Head Gasket – Fits Mercury V6 150/175 HP 2.0L Outboards (Replaces 27-79583-1, 27-79583)

$29.97 $47.00

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Head Gasket – Fits Mercury V6 150/175 HP 2.0L Outboards (Replaces 27-79583-1, 27-79583) is backordered and will ship as soon as it is back in stock.

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Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This replacement Head Gasket fits Mercury V6 150/175 HP 2.0L Outboards manufactured between 1976 and 1988. It serves as a crucial sealing component between the cylinder head and the engine block, preventing combustion gas leakage and coolant or oil mixing.

It is a direct replacement for Mercury OEM part numbers 27-79583-1, 27-79583, 27-795831, and 67066/79583. It also cross-references with aftermarket parts GLM 35910 and WSM 505-39.

Installation Method: OEM direct replacement; install dry on clean, flat surfaces.
Engine Environment: Designed for 2-stroke marine engines with high temperatures and pressure pulses.
Included Contents: One head gasket per package.

Part Number Matrix

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

Brand	Part Number
Mercury	27-79583-1
Mercury	27-79583
Mercury	27-795831
Mercury	67066/79583
GLM	35910
WSM	505-39

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury and Mariner outboards, check your engine’s serial number against the ranges provided to ensure an exact match.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	V-150	150	2-Stroke	1973–1977	27-79583-1	Serial Range: 4868998-6042945
Mercury	V-150	150	2-Stroke	1982–1990	27-79583-1	Serial Range: 6042946-0C239552
Mercury	V-150 Work	150	2-Stroke	1978–1985	27-79583-1	V-1500 Series
Mercury	V-150-XR-2	150	2-Stroke	1978–1985	27-79583-1	Marathon MAGNUM (V-6)
Mercury	V-150 Marathon	150	2-Stroke	1978–1985	27-79583-1	Marathon MAGNUM (V-6)
Mercury	V-150 Magnum	150	2-Stroke	1978–1985	27-79583-1	Marathon MAGNUM (V-6)
Mercury	V-175	175	2-Stroke	1976–1981	27-79583-1	Made in USA, Serial Range: 4301235-6618750
Mercury	V-175	175	2-Stroke	1976–1979	27-79583-1	Made in AUS, Serial Range: 8058870 and Up

Technical Specs

Product Type: Cylinder Head Gasket
Installation: OEM Direct Replacement
Fuel Type: Gasoline
Housing Material: Fiber-Elastomer Composite (AFM Material)
Product Dimensions: Length: 47.0; Width: 17.5; Height: 0.4;
Thickness: 1.0 mm (0.039")
Bore Size: 3.125" (79.4 mm)
Working Pressure: Rated for marine two-stroke environments with elevated temperatures and pressure pulses
Other Technical Attributes: Made with Victor Reinz AFM 1.0MM material - non-asbestos aramid fibers and elastomeric binders bonded to steel core

What’s in the Box

1 x Head Gasket (Replaces 27-79583-1/27-79583/27-795831)

Installation Notes

Disconnect the battery and completely drain the cooling system.
Remove the cylinder head cover, spark plugs, and any other components obstructing access to the head bolts.
Following the service manual's specified pattern, loosen the head bolts in several passes to prevent warping the head.
Carefully lift the cylinder head from the engine block. Never pry between the head and block.
Remove the old head gasket. Thoroughly clean and inspect both the engine block and cylinder head mating surfaces. They must be perfectly flat, clean, and dry.
Position the new head gasket on the engine block, confirming its orientation with the dowel pins. Do not use any sealant.
Gently lower the cylinder head back into place over the gasket and dowel pins.
Install the head bolts and torque them in the correct sequence and stages according to your engine’s service manual specifications. This is critical for a proper seal.
Reassemble all previously removed components.
Refill the cooling system with the recommended coolant mixture.
Reconnect the battery, start the engine, and carefully check for any coolant, oil, or exhaust leaks around the head.

Troubleshooting & FAQ

How do I know if this head gasket fits my engine?

This gasket is specifically designed for Mercury/Mariner 150-175 HP, 2-Stroke V6 2.0L engines from approximately 1976–1988. To guarantee fitment, please refer to the detailed 'Engine & Model Compatibility' table and match your engine's model, year, and serial number range.

What are the signs of a blown head gasket?

Common symptoms include significant engine overheating, a noticeable loss of compression or power, white smoke from the exhaust (burning coolant), bubbles in the radiator or coolant overflow tank, and milky-white engine oil (indicating coolant contamination).

Should I use sealant or adhesive when installing this gasket?

No. This head gasket is designed to be installed dry. The mating surfaces on both the engine block and cylinder head must be meticulously cleaned of all old gasket material, oil, and debris before installation. The use of sealant can interfere with the seal and cause premature failure.

What material is this gasket made from?

It is constructed from a high-performance Victor Reinz AFM 1.0MM material, which is a fiber-elastomer composite. This material uses non-asbestos aramid fibers and elastomeric binders bonded to a steel core, providing excellent sealing and durability in high-pressure, high-temperature marine environments.

Can I reuse my old head gasket?

Absolutely not. Head gaskets are single-use, "crush" type components. They are designed to deform upon torquing to create a perfect seal. Once compressed, they cannot be reused and must be replaced whenever the cylinder head is removed.

How often should a head gasket be replaced?

Head gaskets do not have a standard replacement interval. They are typically only replaced when they fail or during a major engine rebuild. Their lifespan depends on engine condition, operating habits, and proper installation.

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.

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