Gasket – Fits Mercury/Mercruiser 120-160 HP (Replaces 27-39915)
Gasket – Fits Mercury/Mercruiser 120-160 HP (Replaces 27-39915) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Gasket – Fits Mercury/Mercruiser 120-160 HP (Replaces 27-39915)
Product Details
This aftermarket Gasket – Fits Mercury/Mercruiser 120-160 HP is engineered for exhaust elbow mounting on a range of 4-stroke sterndrive and inboard engines, primarily from 1964 to 1982. It also fits various other models including the MerCruiser 3.0L, 496 Magnum, 8.1S, and specific V6/V8 applications requiring an open riser gasket.
This part is a direct replacement for Mercury OEM part 27-39915 and serves as an interchange for Sierra 18-2819 and GLM 31410.
- Designed for exhaust elbow mounting.
- Suitable for open exhaust riser systems on select V6 and V8 engines.
- Engineered for both sterndrive and inboard engine configurations.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 27-39915 |
| Sierra | 18-2819 |
| GLM | 31410 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This gasket fits a wide range of Mercury/Mercruiser engines. Please check your engine's serial number for precise fitment where noted.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury/Mercruiser | 120 GM 153 I/L4 | 120 | 4-Stroke | 1964–1972 | 27-39915 | Serial range: 1666601 THRU 3377340 |
| Mercury/Mercruiser | 120 GM 153 I/L4 | 120 | 4-Stroke | 1972–1978 | 27-39915 | Serial range: 3377341 THRU 5192048 |
| Mercury/Mercruiser | 120 GM 153 I/L4 | 120 | 4-Stroke | 1979–1982 | 27-39915 | Serial range: 5192049 THRU 6229717 |
| Mercury/Mercruiser | 160 GM 250 I/L6 | 160 | 4-Stroke | 1967–1969 | 27-39915 | Serial range: 2048022 THRU 2770031 |
| Mercury/Mercruiser | MerCruiser 3.0 | 4-Stroke | 27-39915 | Exhaust Elbow Gasket application. | ||
| Mercury/Mercruiser | 496 Magnum | 4-Stroke | 27-39915 | Sterndrives and inboard engines. | ||
| Mercury/Mercruiser | 8.1S | 4-Stroke | 27-39915 | Sterndrives and inboard engines. | ||
| Mercury/Mercruiser | V6 (Open) | 27-39915 | For 4.3L engines (Repowermarine.com) | |||
| Mercury/Mercruiser | V8 (Open) | 27-39915 | For 5.0L, 5.7L, and 7.4L engines (Repowermarine.com) |
Technical Specs
- Product Type
- Gasket
- Installation
- Exhaust Elbow Mounting
- Dimensions
- Length: 0.13 in | Width: 6.0 in | Height: 7.5 in
- Weight
- 141.75 g (5 ounces)
- Other Technical Attributes
- Suitable for 496 Magnum and 8.1S MerCruiser sterndrives and inboard engines (Norcalcarculture.com). Open exhaust riser gasket for Mercruiser 4.3L V6, 5.0L, 5.7L, 7.4L V8 engines (Repowermarine.com)
- Warranty
- Amazon.com Voluntary 30-Day Return Guarantee
What’s in the Box
- 1 x Gasket (Replaces 27-39915)
Installation Notes
- Disconnect the battery and ensure the engine is completely cool.
- Drain the cooling system as needed to access the exhaust components.
- Carefully remove the bolts securing the exhaust elbow or riser.
- Remove the old gasket and thoroughly clean both mating surfaces. Ensure they are free of old gasket material, rust, and debris.
- Position the new gasket correctly. Do not use sealant unless specified by the engine manufacturer's service manual.
- Reinstall the exhaust elbow/riser and tighten fasteners to the manufacturer's recommended torque specifications in the correct sequence.
- Refill the cooling system, reconnect the battery, and start the engine. Check for any exhaust or water leaks.
Troubleshooting & FAQ
Which specific Mercury/Mercruiser engines does this gasket fit?
This gasket fits a variety of models, including the 120 HP and 160 HP I/L4 and I/L6 engines from 1964–1982, as well as the 3.0L, 496 Magnum, 8.1S, and certain V6 (4.3L) and V8 (5.0L, 5.7L, 7.4L) engines. Please refer to the compatibility table and your engine's serial number for an exact match.
What are the signs of a failed exhaust elbow gasket?
Common symptoms of a bad gasket include water leaking externally from the joint between the manifold and elbow, engine overheating, or in severe cases, water entering the engine cylinders, which can cause catastrophic damage.
Should I use sealant or adhesive when installing this gasket?
In most cases, this gasket is designed to be installed dry on clean, flat surfaces. Applying sealant can cause it to squish out and create an uneven seal or block passages. Always consult your engine's official service manual for specific recommendations.
How do I know if this is the correct gasket for my engine?
The best way to confirm is by matching the OEM part number (27-39915) with the one listed in your engine's part diagram. You should also visually compare the gasket shape to your old part before installation.
What is the difference between an "open" and "closed" riser gasket?
This is an "open" style gasket, meaning it allows for the free flow of raw water through the cooling passages. It is not compatible with systems that require a "closed" or "blocked" gasket, which restricts water flow for certain cooling configurations.
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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