Exhaust Manifold Gasket – Fits Mercury 15-25hp Outboards (Replaces 27-414758)
Exhaust Manifold Gasket – Fits Mercury 15-25hp Outboards (Replaces 27-414758) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Exhaust Manifold Gasket – Fits Mercury 15-25hp Outboards (Replaces ...
Product Details
This Exhaust Manifold Gasket for Mercury 15-25hp Outboards is designed for 2-Stroke Mercury Marine engines from 15 to 25 horsepower, manufactured from 1978 to the present. It ensures a proper seal between the exhaust manifold and the powerhead.
It serves as a direct aftermarket replacement for Mercury part number 27-414758.
- Installation: Direct OEM replacement fit.
- Connection: Seals the exhaust manifold to the powerhead.
- Material: Engineered for gasoline marine environments.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 27-414758 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury Marine engines, please verify your model and year falls within the specified range.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Mercury | 15-25hp | 15-25 | 2-Stroke | 1978–present | 27-414758 |
Technical Specs
- Product Type
- Exhaust Manifold Gasket
- Installation
- Direct OEM replacement
- Fuel Type
- Gasoline
- Connection
- Exhaust manifold to powerhead
- Dimensions
- 19.0" L x 15.0" H x 0.2" W
- Fitting Type
- Direct fit
What’s in the Box
- 1 x Exhaust Manifold Gasket (Replaces 27-414758)
Installation Notes
- Ensure the engine is completely cool and disconnect the battery for safety.
- Remove the engine cowling to access the powerhead and exhaust manifold.
- Carefully unbolt and remove the exhaust manifold from the powerhead.
- Remove the old gasket and thoroughly clean both mating surfaces of any old material or carbon buildup.
- Position the new gasket correctly onto the powerhead mounting studs or dowels.
- Reinstall the exhaust manifold, ensuring bolts are tightened evenly and to the manufacturer's recommended torque specifications.
- Reconnect the battery, start the engine, and check for any exhaust leaks around the manifold.
Troubleshooting & FAQ
How do I know if this gasket will fit my engine?
This gasket is designed for Mercury 15-25hp 2-Stroke outboards from 1978-present. The most reliable way to confirm fitment is to match your original part number to the direct replacement number: Mercury 27-414758. Always compare the photos to your old part.
What are the signs of a failed exhaust manifold gasket?
Common symptoms include a noticeably louder exhaust noise, the smell of exhaust fumes around the engine, visible smoke leaking from the side of the powerhead, and potential loss of performance or rough idling due to improper back pressure.
Do I need to use sealant with this gasket?
In most cases, this gasket is designed to be installed dry. However, always refer to your engine's official service manual for specific instructions, as some models or conditions may call for a light application of a specific high-temperature marine sealant.
When should I replace my exhaust manifold gasket?
There is no specific service interval. The gasket should be replaced any time the exhaust manifold is removed for other service, or immediately if you detect signs of a leak (noise, fumes, visible exhaust).
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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