Inner Exhaust Plate Gasket – Fits Mercury Marine 100/115/125 HP 4-Cylinder (Replaces 27-812775A01)

$45.99

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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 is a replacement Inner Exhaust Plate Gasket designed for Mercury Marine 4-cylinder outboard engines, including 80 Jet, 100 HP, 115 HP, and 125 HP 4-Stroke models. It ensures a proper seal for the inner exhaust plate, preventing leaks and maintaining engine performance.

It serves as a direct replacement for Mercury OEM part numbers 27-812775A01, 27-8127751, and 27-812775-5, and interchanges with GLM part 37680.

Engineered for direct replacement installation.
Specifically designed for inner exhaust plate applications.
Built to withstand the high-temperature marine exhaust environment.

Part Number Matrix

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

Brand	Part Number	Superseded By	Notes
Mercury Marine	27-812775-5	27-8127751	Original Part
Mercury Marine	27-8127751	27-812775A01	Superseded Part
Mercury Marine	27-812775A01		Current OEM Part
GLM	37680		Aftermarket Cross-Reference

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This gasket is designed for select Mercury Marine 4-cylinder outboard engines.

Brand	Model	Rated HP	Stroke	OEM Part No.	Notes
Mercury Marine	4-Cylinder Outboard	80 Jet	4-Stroke	27-812775A01	Inner exhaust plate application
Mercury Marine	4-Cylinder Outboard	100	4-Stroke	27-812775A01	Inner exhaust plate application
Mercury Marine	4-Cylinder Outboard	115	4-Stroke	27-812775A01	Inner exhaust plate application
Mercury Marine	4-Cylinder Outboard	125	4-Stroke	27-812775A01	Inner exhaust plate application

Technical Specs

Product Type: Exhaust Plate Gasket
Application: Inner exhaust plate
Installation: Direct replacement
Dimensions: Length: 22.0 in (558.8 mm), Width: 12.0 in (304.8 mm), Height: 0.25 in (6.35 mm)
Weight: 0.38 lb (0.172 kg)

What’s in the Box

1 x Gasket Set (Replaces 27-812775A01)

Installation Notes

Ensure the engine is off, cool, and disconnected from the battery.
Drain the engine block of any cooling water to prevent spills.
Carefully remove the exhaust cover and plate to access the old gasket.
Remove the old gasket and any residual sealant or debris from the mating surfaces.
Ensure both the engine block and exhaust plate surfaces are perfectly clean and dry.
Position the new gasket correctly, aligning it with all bolt holes.
Reinstall the exhaust plate and cover, tightening bolts to the manufacturer's specified torque sequence and values.
Reconnect the battery, start the engine, and check for any exhaust or water leaks.

Troubleshooting & FAQ

How do I confirm this gasket fits my specific engine model?

The surest way is to match your existing part number to one of the cross-references provided (27-812775A01, 27-8127751, 27-812775-5) or GLM 37680. While this part fits the HP range listed, always verify visually and by part number before ordering.

What are the signs of a failed inner exhaust plate gasket?

Common symptoms include water leaking externally from the engine cowl, engine overheating, loss of power, or an unusually loud exhaust note. A visual inspection may reveal corrosion or water marks around the exhaust plate seam.

Can I reuse my old bolts when installing this new gasket?

It is highly recommended to inspect the original bolts for corrosion, stretching, or damage. For critical components like this, replacing old hardware is a safe practice to ensure a proper seal and prevent future failures.

Is any sealant required with this gasket?

This gasket is typically designed to be installed dry. Applying sealant can interfere with its ability to seal correctly unless explicitly required by your engine's service manual. Always clean surfaces thoroughly before installation.

What is the difference between an inner and outer exhaust gasket?

The inner gasket seals the exhaust plate directly to the engine block, while an outer gasket seals the exhaust cover to the plate. They have different shapes and are not interchangeable. This part is for the inner application.

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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