Cylinder Block Cover Gasket – Fits Mercury/Mariner 90-115hp Inline (Replaces 27-981853)

$16.09 $25.00

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Product Details

This aftermarket Cylinder Block Cover Gasket provides a precise seal for Mercury/Mariner 90-115hp Inline 6 engines manufactured in 1978 and later. It is designed for 90hp models with serial number 5594657 & Up and 115hp models with serial number 5600967 & Up.

It serves as a direct replacement for Quicksilver part number 27-981853 and Mercury part number 981853, ensuring reliable performance in marine environments.

Engineered as a direct replacement for a secure fit.
Primarily used for the cylinder block cover, with applications in water pump systems.
Package includes one ready-to-install gasket.

Part Number Matrix

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

Brand	Part Number
Mercury	981853
Quicksilver	27-981853

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury/Mariner engines, verify your model's serial number falls within the specified range to ensure correct fitment.

Brand	Model	Rated HP	Years	OEM Part No.	Notes
Mercury/Mariner	Inline	90	1978 and later (S/N 5594657 & Up)	27-981853	Cylinder block cover gasket
Mercury/Mariner	Inline	115	1978 and later (S/N 5600967 & Up)	27-981853	Cylinder block cover gasket

Technical Specs

Product Type: Cylinder Block Cover Gasket
Installation: Direct replacement
Fuel Type: Gasoline
Dimensions: Height: 7.25 in; Width: 27.75 in; Length: 1.25 in
Weight: 0.11 kg (0.25 lb)
Warranty: No warranty (OEM part)
Other Technical Attributes: Used for water pump applications

What’s in the Box

1 x Gasket (27-981853)

Installation Notes

Disconnect the battery and drain the cooling system as needed.
Remove any components obstructing access to the cylinder block cover.
Carefully unbolt and remove the old cover, taking note of bolt positions.
Remove the old gasket and thoroughly clean both the engine block and cover surfaces. Ensure they are free from all old gasket material, oil, and debris.
Position the new gasket correctly on the engine block.
Reinstall the cylinder block cover, ensuring it is properly aligned.
Install and tighten the bolts in the sequence and to the torque specified in your engine's service manual.
Reassemble all other components, refill fluids, and reconnect the battery.
Start the engine and carefully inspect for any leaks around the cover.

Troubleshooting & FAQ

How do I confirm this gasket fits my specific engine?

This gasket fits Mercury/Mariner 90hp engines with serial number 5594657 & Up and 115hp engines with serial number 5600967 & Up, from 1978 onwards. Always verify your engine's serial number before ordering.

Is this a water pump gasket or a cylinder block cover gasket?

Its primary identification is a cylinder block cover gasket. However, depending on the engine diagram, it may also be referenced in relation to water cooling passages, leading some sources to mention water pump applications.

What are the signs of a failing cylinder block cover gasket?

Common symptoms include visible water or oil leaks from the side of the engine block, engine overheating, or a loss of compression. Any visible crack or degradation on the old gasket during inspection indicates a need for replacement.

Does this gasket require a sealant upon installation?

Typically, 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 or dressing 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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