Mercury Marine Gasket (27-127754) – Fits Mercury/Mercruiser 2.0L-2.5L EFI Models

$35.04

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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 aftermarket Mercury Marine Gasket (27-127754) is engineered for a precise fit on Mercury/Mercruiser high-performance race outboard engines and various 2.0L to 2.5L EFI models manufactured from the late 1970s through the 2000s. It functions as a cylinder head plate gasket for the reed block assembly.

This part is a direct replacement for Mercury part numbers 27-12775, 27-127751, 27-127752, 27-127753, and 27-78298.

Critical for sealing the reed block and cylinder head assembly.
Engineered to meet or exceed OEM material and performance standards.
Includes one gasket as shown.

Part Number Matrix

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

Brand	Part Number	Notes
Mercury	27-12775	Superseded by 27-127754
Mercury	27-127751	Superseded by 27-127754
Mercury	27-127752	Superseded by 27-127754
Mercury	27-127753	Superseded by 27-127754
Mercury	27-78298	Superseded by 27-127754
Sea Sierra (Aftermarket)	27-127754	Current direct replacement

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury and Mariner outboards, always verify 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-200	200	2-Stroke	1978–1988	27-127754	Serial range: 5624878-0C100860
Mercury	V-225		2-Stroke		27-127754
Mercury/Mariner	2.5L EFI		2-Stroke		27-127754	Serial range: 0D935271-0G366999
Mercury/Mariner	2.5L EFI		2-Stroke		27-127754	Serial range: 0G367000-0G610238
Mercury/Mariner	2.5L EFI/EFI-OFFSHORE		2-Stroke		27-127754	Serial range: 0G367000-0G610238
Mercury/Mariner	2.5L EFI/EFI-OFFSHORE		2-Stroke		27-127754	Serial range: 0G610239-0G856999
Mercury/Mariner	2.5L EFI/EFI-OFFSHORE		2-Stroke		27-127754	Serial range: 0G857000-0T999519
Mercury	FORMULA I (2 LITRE EFI)		2-Stroke		27-127754	Serial range: 0A953232-0A953245
Mercury	S3000		2-Stroke		27-127754	Serial range: 0D181027 & Up

Technical Specs

Product Type: Cylinder Head Plate Gasket
Dimensions: 14.0 × 7.0 × 1.06 in (approx. 355.6 × 177.8 × 26.9 mm)
Weight: 0.122 kg (0.27 lb)
Other Technical Attributes: Used in reed block and cylinder head assembly

What’s in the Box

1 × GASKET (27-127754)

Installation Notes

Ensure the engine is completely cool and disconnect the battery for safety.
Drain the engine coolant to a level below the cylinder head assembly.
Carefully remove any components obstructing access to the reed block and cylinder head plate.
Remove the old gasket and meticulously clean both mating surfaces. Ensure they are free of any old gasket material, oil, or residue.
Position the new gasket correctly, ensuring it is properly aligned with all bolt holes and passages. Do not use sealant unless specified by your service manual.
Reassemble all components and tighten fasteners to the manufacturer's specified torque sequence and values to ensure an even seal.

Troubleshooting & FAQ

How do I confirm this gasket fits my engine?

Check your engine's model, horsepower, and especially its serial number against the ranges listed in the compatibility table. This gasket is specific to certain 2.0L-2.5L EFI models, and verifying the serial number is critical for a correct fit.

What are the signs of a failing head plate gasket?

Common symptoms include poor engine performance, loss of compression, unexplained coolant or fuel leaks around the cylinder head and reed block area, and potential engine overheating.

Can I reuse my old gasket or this new one?

No. This gasket is a single-use, crush-type part. It is designed to deform upon installation to create a perfect seal and must be replaced whenever the components are disassembled.

Do I need to use a sealant with this gasket?

Typically, this gasket is designed to be installed dry. However, always consult your engine's official service manual, as some specific procedures might recommend a light application of a specific sealant.

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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