Exhaust Elbow Gasket – Fits MerCruiser 120, 140/3.0L, 470, V8 Engines (Replaces 27-99777-2)
Exhaust Elbow Gasket – Fits MerCruiser 120, 140/3.0L, 470, V8 Engines (Replaces 27-99777-2) 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 Elbow Gasket – Fits MerCruiser 120, 140/3.0L, 470, V8 Engin...
Product Details
This Exhaust Elbow Gasket – Fits MerCruiser 120, 140/3.0L, 470, V8 Engines (Replaces 27-99777-2) is designed for a precise fit on a range of MerCruiser sterndrive and inboard engines. It is compatible with 120 series (1983 and newer), 140/3.0L, 470, 165 inline 6-cylinder, GM V-8 small block (1982 and older) with standard cooling, and Ford V-8 engines.
This part provides a direct interchange for Mercury/MerCruiser 27-52076, 27-99777, 27-997771, 27-997772, 27-99777B2, Sierra 18-2833-9, Mallory 9-61407, GLM 31520, Barr MC472799777, and Osco 52076.
- Installation: Simple bolt-on application between the exhaust manifold/riser and elbow.
- Cooling System: Designed for use with standard cooling systems.
- Material: Constructed from a durable composite material to ensure a reliable seal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 27-52076 |
| Mercury/MerCruiser | 27-99777 |
| Mercury/MerCruiser | 27-997771 |
| Mercury/MerCruiser | 27-997772 |
| Mercury/MerCruiser | 27-99777B2 |
| Sierra | 18-2833-9 |
| Mallory | 9-61407 |
| GLM | 31520 |
| Barr | MC472799777 |
| Osco | 52076 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser owners, verify your engine model from the chart. Note that this gasket is specified for older GM V8 small block engines with standard cooling systems.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 120 | 120 | 4-Stroke | 1983 and newer | 27-997772 | |
| MerCruiser | 140/3.0L | 140 | 4-Stroke | All years | 27-997772 | |
| MerCruiser | 165 inline 6-cylinder | 165 | 4-Stroke | All years | 27-997772 | |
| MerCruiser | V8 small block (GM) | Various | 4-Stroke | Up to 1982 | 27-997772 | Standard cooling only |
| MerCruiser | V8 (Ford) | Various | 4-Stroke | All years | 27-997772 |
Technical Specs
- Product Type
- Exhaust Elbow Gasket
- Installation
- Bolt-on
- Connection
- Between exhaust manifold/riser and elbow
- Housing Material
- Composite
- Other Technical Attributes
- Standard cooling systems
- Warranty
- 1 Year
What’s in the Box
- 1 x Exhaust Elbow Gasket (27-99777-2)
Installation Notes
- Ensure the engine is completely cool and disconnect the battery for safety.
- Drain the engine coolant to prevent spills.
- Carefully unbolt and remove the exhaust elbow from the exhaust manifold or riser.
- Thoroughly clean both mating surfaces, removing all traces of the old gasket and any corrosion or debris.
- Position the new gasket correctly, aligning it with the bolt holes. Do not use sealant unless specified by your engine's service manual.
- Reinstall the exhaust elbow and tighten the bolts in a crossing pattern to the manufacturer's recommended torque specifications.
- Refill the cooling system, reconnect the battery, and run the engine while checking for any leaks.
Troubleshooting & FAQ
What are the signs of a failing exhaust elbow gasket?
Common symptoms include visible water leaks or rust trails at the joint between the elbow and manifold, steam emanating from the engine compartment, an unusual drop in coolant levels, or engine overheating. A compromised gasket can allow water to enter the engine, causing severe damage.
Is any sealant required when installing this gasket?
This gasket is designed to be installed dry. Applying sealants can cause the gasket to slip or create an uneven seal. Always clean both mating surfaces meticulously before installation to ensure a proper, leak-free fit.
How often should this gasket be replaced?
The exhaust elbow gasket should be replaced any time the exhaust elbow is removed for service. It's also good practice to inspect it regularly for signs of leaks or deterioration as part of your annual engine maintenance schedule.
Will this gasket fit a closed cooling system?
This particular gasket is specified for engines with standard (raw water) cooling systems. For certain models like the GM V8 small block, it is explicitly not for closed or heavy-duty cooling systems. Always verify your system type before purchase.
What is the difference between OEM and this aftermarket part?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency to ensure reliable performance.
How fast is shipping and what does it cost?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free to most regions, with expedited options appearing at checkout where available based on your location.
What is the warranty and return policy?
Our products are covered by a 1-year warranty against manufacturing defects under normal marine use. If an issue arises, contact our support team with your order details. Returns are accepted within our standard window for items that are unused and in their 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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