Exhaust Elbow Gasket – Fits MerCruiser 2.5L 3.0L V8 (Replaces 27-997771, Sierra 18-2833-9)
Exhaust Elbow Gasket – Fits MerCruiser 2.5L 3.0L V8 (Replaces 27-997771, Sierra 18-2833-9) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Exhaust Elbow Gasket – Fits MerCruiser 2.5L 3.0L V8 (Replaces 27-99...
Exhaust Elbow Gasket – Fits MerCruiser 2.5L 3.0L V8 (Replaces 27-997771, Sierra 18-2833-9) is backordered and will ship as soon as it is back in stock.
Product Details
This Exhaust Elbow Gasket creates a reliable seal between the exhaust manifold and riser on specific MerCruiser engines. It is designed for MerCruiser 2.5L & 3.0L I4 models (1993–current) and pre-1982 GM V8 small block models, both of which utilize wet-joint exhaust systems.
This part is a direct interchange for MerCruiser part numbers 27-52076, 27-99777, 27-997771, 27-997772, and 27-99777B2, as well as aftermarket equivalents like Sierra 18-2833-9, Barr Marine MC472799777, GLM 31520, Mallory 9-61407, and Osco 52076.
- Installs on wet-joint exhaust connections.
- Seals the connection between the exhaust manifold and the exhaust riser/elbow.
- Made from durable composite fiber gasket material.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 27-52076 |
| MerCruiser | 27-99777 |
| MerCruiser | 27-997771 |
| MerCruiser | 27-997772 |
| MerCruiser | 27-99777B2 |
| Sierra | 18-2833-9 |
| Barr Marine | MC472799777 |
| GLM | 31520 |
| Mallory | 9-61407 |
| Osco | 52076 |
| SupremeMarine | 99777 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This gasket fits select MerCruiser I4, I6, and V8 engines, primarily those with wet-joint exhaust systems. Please verify your specific model and year range.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | MCM 120 | 120 | 4-Stroke | 1993 and newer | 27-997771 | |
| MerCruiser | MCM 140/3.0L | 140 | 4-Stroke | All | 27-997771 | |
| MerCruiser | MCM 470 | 170 | 4-Stroke | All | 27-997771 | 3.7L I4 engine |
| MerCruiser | MCM 165 | 165 | 4-Stroke | All | 27-997771 | In-line 6 cyl. |
| MerCruiser | GM V-8 small block | 180-260 | 4-Stroke | 1982 and older | 27-997771 | |
| MerCruiser | Ford V-8 | 180-260 | 4-Stroke | All applicable | 27-997771 |
Technical Specs
- Product Type
- Exhaust Elbow Gasket
- Installation
- Wet Joint
- Connection
- Bolted
- Housing Material
- Composite Fiber Gasket Material
- Housing Color
- Brown/Tan
- Fitting Type
- Exhaust Elbow to Manifold
- Other Technical Attributes
- Seals connection between exhaust manifold and exhaust riser/elbow
What’s in the Box
- 4 x Exhaust Elbow Gasket (Replaces 27-99777, 27-997771)
Installation Notes
- Ensure the engine is completely cool and the battery is disconnected before starting.
- Drain coolant from the manifold if necessary, and then carefully unbolt and remove the exhaust riser/elbow.
- Thoroughly remove all traces of the old gasket material from both the manifold and the elbow mating surfaces. Avoid scratching the metal surfaces.
- Position the new gasket onto the manifold, aligning it with the bolt holes. Do not use any sealant unless expressly required by your engine’s service manual.
- Reinstall the exhaust riser/elbow and tighten the bolts in the sequence and to the torque values specified by the manufacturer.
- Once reassembled, reconnect the battery, refill coolant if drained, and run the engine while checking for any exhaust or water leaks around the new seal.
Troubleshooting & FAQ
What are the signs of a failing exhaust elbow gasket?
Common symptoms include visible water leaks around the exhaust manifold and riser joint, steam emerging from the engine compartment, a strong exhaust fume smell, or engine overheating alarms caused by water ingestion or coolant loss.
Is this a "wet-joint" or "dry-joint" gasket?
This is a wet-joint gasket, specifically designed for exhaust systems where engine coolant passes through the connection between the manifold and riser. Verify your engine's system type via its service manual before ordering.
Can I reuse my old gasket?
No. Gaskets are single-use components designed to compress and create a seal under specific pressure. Once used and heat-cycled, they lose their integrity and will not seal properly again.
Do I need to apply sealant to this gasket during installation?
These composite gaskets are typically designed to be installed dry. Applying sealants can interfere with the seal and may even cause the gasket to slip out of place during torquing. Always follow the recommendations in your specific engine's service manual.
How can I tell if my older V8 engine has a wet-joint system?
Generally, MerCruiser small block V8 engines from 1982 and older use a wet-joint design. You can confirm by inspecting your current setup; wet-joint systems will have large water passages integrated into the gasket and mating surfaces.
What happens if I use the wrong gasket?
Using an incorrect gasket can lead to catastrophic engine damage. A dry-joint gasket on a wet-joint system will block coolant flow, causing rapid overheating. A wet-joint gasket on a dry-joint system can introduce water where it doesn't belong, leading to corrosion or hydrostatic lock.
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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