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Exhaust Plate Gasket – Fits Mercury/Mariner 80-125 HP Outboard (Replaces 27-8127755)

Sale price $18.50 Regular price $29.00
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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

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 is a new aftermarket Exhaust Plate Gasket designed for Mercury and Mariner 80–125 HP, 4-Stroke Inline 4 outboard engines manufactured between 1994 and 1998. It ensures a proper seal between the exhaust plate and the engine block, preventing leaks and maintaining performance.

This part is a direct replacement for Mercury OEM part numbers 27-8127755, 27-812775A01, 8127755, 812775006, 8127751 and aftermarket number WSM 521-27.

  • Installs externally between the engine block and the exhaust plate.
  • Engineered to fit exhaust plate castings #44324C2 and #44325C2.
  • Made from high-quality, OEM-grade gasket material for durability and a reliable seal.

Part Number Matrix

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

Brand Part Number Superseded By
Mercury 27-8127755 27-812775A01
Mercury 8127755
Mercury 812775006
Mercury 8127751
WSM 521-27

Engine & Model Compatibility

Confirm your engine model and year in the table below.

Fits various 4-cylinder, 4-stroke outboard engines from Mercury and Mariner in the 80–125 HP range.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Mercury 4 Cyl Jet 80 4-Stroke 1994–1998 27-8127755 Superseded by 27-812775A01
Mercury 4 Cyl 3.500 Bore Looper 100 4-Stroke 1994–1998 27-8127755 Superseded by 27-812775A01
Mercury 4 Cyl 3.500 Bore Looper 115 4-Stroke 1994–1998 27-8127755 Superseded by 27-812775A01
Mercury 4 Cyl 3.500 Bore Looper 125 4-Stroke 1994–1998 27-8127755 Superseded by 27-812775A01
Mariner 80-125 HP Models 80-125 4-Stroke 1994–1998 27-8127755 Inline 4 engines only

Technical Specs

Product Type
Exhaust Plate Gasket
Installation
External mount between exhaust plate and block
Housing Material
OEM-quality gasket material
Dimensions
10.5" x 24.0" x 0.25"
Other Technical Attributes
For exhaust plate casting #44324C2 and #44325C2

What’s in the Box

  • 1 x Exhaust Plate Gasket (Replaces 27-8127755/27-812775A01)

Installation Notes

  1. Ensure the engine is off and cool to the touch. Disconnect the battery for safety.
  2. Drain the engine block's cooling system to prevent water spills.
  3. Carefully unbolt and remove the exhaust plate cover from the engine block.
  4. Remove the old gasket and thoroughly clean any residue from both mating surfaces until smooth and bare.
  5. Position the new gasket, verifying it aligns with all bolt holes and passages.
  6. Reinstall the exhaust plate cover. Tighten bolts in a crisscross pattern to the manufacturer-specified torque.
  7. Reconnect the cooling system and battery terminals.
  8. Start the engine and carefully inspect for any signs of water or exhaust leaks around the newly sealed area.

Troubleshooting & FAQ

How do I know if my exhaust plate gasket is failing?

Common signs of a bad gasket include visible water leaks around the exhaust plate, engine overheating, a noticeable loss of power, or an unusual-sounding exhaust. A visual inspection may reveal corrosion or physical damage to the gasket.

Will this gasket fit my 1999 Mercury 115 HP engine?

No, this specific gasket is designed for models manufactured between 1994 and 1998. Always verify compatibility using your engine's model and serial number against the provided tables before purchasing.

What is special about the exhaust plate casting numbers?

The casting numbers (#44324C2 and #44325C2) refer to the specific exhaust plate parts this gasket was designed to fit. It's a precise way to confirm component matching, as manufacturers can have multiple designs for the same engine model.

Do I need to use a sealant with this gasket?

Generally, modern gaskets like this are designed to be installed dry. However, always consult your engine's official service manual, as it may recommend a specific sealant for your 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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