Thermostat Cover Gasket – Fits Mercury/Mariner 6-15 HP (Replaces 27-19205002)

$2.93 $4.00

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Product Details

This aftermarket Thermostat Cover Gasket provides a reliable seal for the thermostat housing on Mercury and Mariner 6-15 HP 2-stroke outboard engines from 1990 and newer. It is designed to ensure a precise fit and prevent coolant leaks, maintaining optimal engine operating temperature.

It serves as a direct replacement for Mercury OEM part numbers 27-19205002, 27-192051, and 27-14672, and also interchanges with aftermarket parts GLM 14500 and Sierra 18-0998.

Installs as a direct replacement for original parts.
Engineered from durable composite gasket material for a lasting seal.
Essential for preventing coolant leaks and engine overheating.

Part Number Matrix

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

Brand	Part Number
Mercury	27-19205002
Mercury	27-192051
Mercury	27-14672
GLM	14500
Sierra	18-0998

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury and Mariner models, it is critical to verify your engine's serial number falls within the specified ranges to ensure correct fitment.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	Outboard	6	2-Stroke	1990 and up	27-19205002	Serial number 0P325500 & Up
Mercury	Outboard	8	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up, 0T980000-0T999999, 1B000001 & Up
Mercury	Outboard	9.9	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up, 0T980000-0T999999, 1B000001 & Up
Mercury	Marathon	10	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up, 0T980000-0T999999, 1B000001 & Up
Mercury	Sea Pro	10	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up, 0T980000-0T999999, 1B000001 & Up
Mercury	Viking	10	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up
Mercury	Outboard	15	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up, 0T980000-0T999999, 1B000001 & Up
Mercury	Marathon	15	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up, 0T980000-0T999999, 1B000001 & Up
Mercury	Sea Pro	15	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up, 0T980000-0T999999, 1B000001 & Up
Mercury	Viking	15	2-Stroke	1990 and up	27-19205002	Serial numbers 0P325500 & Up
Mariner	Outboard	6-15	2-Stroke	1990 and up	27-19205002

Technical Specs

Product Type: Thermostat Cover Gasket
Installation: Direct replacement
Material: Gasket material (composite)
Dimensions: 10.5 × 10.5 × 0.1 in (266.7 × 266.7 × 2.54 mm)

What’s in the Box

1 x Thermostat Cover Gasket (Replaces 27-19205002)

Installation Notes

Ensure the engine is completely cool and disconnect the battery for safety.
Locate the thermostat housing on the engine block.
Carefully unbolt and remove the thermostat cover.
Remove the old gasket and thoroughly clean both the cover and housing mating surfaces. Ensure all old gasket residue is gone.
Position the new gasket, aligning it with the bolt holes.
Reinstall the cover and tighten the bolts to the manufacturer-specified torque in a cross pattern.
Reconnect the battery, start the engine, and meticulously check for any coolant leaks as the engine warms up.

Troubleshooting & FAQ

How do I know if this gasket will fit my engine?

This gasket fits Mercury/Mariner 6–15 HP 2-stroke outboards from 1990 and newer. The most reliable way to confirm fitment is to check your engine's serial number against the ranges listed in the compatibility table.

What are the signs of a failed thermostat cover gasket?

Common signs include visible coolant leaks (drips or residue) around the thermostat housing, engine overheating alarms, or steam coming from the engine cowling.

Should I use sealant with this gasket?

This gasket is designed to be installed dry. Applying sealant is generally not required or recommended, as it can interfere with the seal. Always clean the mating surfaces thoroughly before installation.

How often should this gasket be replaced?

The gasket should be replaced any time the thermostat cover is removed for service, such as during a thermostat replacement. It is also good practice to inspect it for degradation or leaks during routine annual maintenance.

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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