Mercury Thermostat Cover Gasket 14318005
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Mercury 14318005 is a genuine OEM thermostat cover gasket for select Mercury and Mariner 2-stroke outboards. Current Mercury dealer references identify it as 27-14318005 GASKET / GASKET-THREM COVR, and show it as the current replacement for older thermostat-cover gasket numbers in the same family.
Key Features
- Genuine Mercury Marine OEM part number 14318005 / 27-14318005.
- Cataloged as a thermostat cover gasket.
- Current dealer listing shows UPC 745061584112.
- Current shipping specs are approximately 0.02 lb, 2.25 in. x 1.50 in. x 0.25 in.
Engine Compatibility
The strongest supportable fitment for 14318005 is Mercury and Mariner small 2-stroke outboards, especially 15 HP Sea Pro / Marathon, 20 HP / 20 Jet, 25 HP / 25 Sea Pro / Marathon / Super 15, 25XS, and 18XD / 20XD / 25XD families shown in current Mercury-oriented parts references. Broader cross-reference sources also connect it to 6 / 8 / 9.9 / 10 / 15 HP applications, but the clearest current Mercury-oriented support is the 15/20/25 and XD families above.
Serial Number Fitment Notice
Verify fitment by exact outboard serial number and the correct cylinder block / thermostat cover diagram before ordering. Current Mercury supersession pages show older gasket numbers rolling into 14318005 across multiple serial breaks, so serial-based confirmation is the safest way to match the correct thermostat cover gasket.
When This Part Needs Replacement
Replace this gasket whenever the thermostat cover is removed, or when the existing gasket is leaking, compressed, damaged, or no longer sealing correctly. Since it is the thermostat cover sealing gasket, renewing it during thermostat service is usually the right move instead of reusing an older gasket. This is a practical service inference supported by its documented thermostat-cover role.
Installation Notes
Install 14318005 only after confirming the correct Mercury thermostat cover and cylinder block diagram for the outboard being serviced. Current parts references show it paired with thermostat-cover and thermostat components in the cylinder block / covers section, so it should be matched to the exact cover style and serial range before reassembly.
Alternate/Superseded Part Numbers
Current sources connect 14318, 143182, 143183, and 143184 as earlier Mercury OEM numbers superseded to 14318005. Related aftermarket cross-references include Sierra 18-0323, GLM 32760, and AM27-14318005.
Parts Desk Insight
For small outboard cooling parts like this, the important match is the thermostat cover style and serial range, not just the horsepower decal. A quick serial-number check usually avoids ordering the wrong gasket from a very similar older superseded family.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
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