Exhaust Elbow Gasket for MerCruiser 120, 140/3.0L, 165, 470 and V8 Engines – Replaces 27-99777-2
Exhaust Elbow Gasket for MerCruiser 120, 140/3.0L, 165, 470 and V8 Engines – Replaces 27-99777-2 is backordered and will ship as soon as it is back in stock.
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Exhaust Elbow Gasket for MerCruiser 120, 140/3.0L, 165, 470 and V8 ...
Exhaust Elbow Gasket for MerCruiser 120, 140/3.0L, 165, 470 and V8 Engines – Replaces 27-99777-2 is backordered and will ship as soon as it is back in stock.
Product Details
This exhaust elbow gasket is an aftermarket replacement designed for selected MerCruiser sterndrive and inboard applications. The listed fitment includes MerCruiser 120 engines from 1983 and newer, 140/3.0L engines, 165 inline six-cylinder engines, 470 engines, older GM V8 small-block engines with standard cooling, and Ford V8 engines. Always compare the original gasket, exhaust elbow configuration, cooling-system type, and engine model before ordering.
This gasket is listed as a replacement or interchange for Mercury/MerCruiser 27-52076, 27-99777, 27-997771, 27-997772, and 27-99777B2, along with Sierra 18-2833-9, Mallory 9-61407, GLM 31520, Barr MC472799777, and Osco 52076.
- Application: Installs between the exhaust manifold or riser and the exhaust elbow.
- Cooling system: Listed for standard cooling systems; certain older GM V8 applications may exclude closed or heavy-duty cooling systems.
- Construction: Composite gasket material intended to provide a dependable seal at the exhaust elbow connection.
- Installation: Direct bolt-on replacement when the gasket profile and bolt pattern match the original part.
Part Number Matrix
Use the following references to compare the gasket with the part being replaced. These numbers should be confirmed against the engine and exhaust-system configuration before installation.
| 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
The applications below reflect the listed model, year, horsepower, and cooling-system conditions. Because exhaust configurations can vary by serial range and cooling arrangement, verify the original part and the complete engine identification before purchase.
| Brand | Model | Rated HP | Stroke | Years | Reference Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 120 | 120 | 4-Stroke | 1983 and newer | 27-997772 | Verify exact exhaust configuration. |
| MerCruiser | 140/3.0L | 140 | 4-Stroke | All years | 27-997772 | Verify gasket profile and bolt pattern. |
| MerCruiser | 165 inline 6-cylinder | 165 | 4-Stroke | All years | 27-997772 | Verify exact exhaust configuration. |
| MerCruiser | 470 | 170 | 4-Stroke | Application listed; confirm year and serial range | 27-997772 | Match the original gasket before ordering. |
| MerCruiser | V8 small block (GM) | Various | 4-Stroke | Up to 1982 | 27-997772 | Standard cooling only; confirm cooling-system type. |
| MerCruiser | V8 (Ford) | Various | 4-Stroke | All years | 27-997772 | Verify engine and exhaust configuration. |
Technical Specs
- Product Type
- Exhaust elbow gasket
- Installation
- Bolt-on replacement
- Connection
- Between the exhaust manifold or riser and exhaust elbow
- Material
- Composite
- Cooling-system application
- Standard cooling systems as listed; verify configuration before installation
- Product format
- Single gasket
What’s in the Box
- 1 x Exhaust elbow gasket
Installation Notes
- Ensure the engine is completely cool and disconnect the battery for safety.
- Drain the applicable cooling water or coolant as necessary to prevent spills.
- Carefully unbolt and remove the exhaust elbow from the exhaust manifold or riser.
- Thoroughly clean both mating surfaces, removing the old gasket, corrosion, and debris.
- Position the new gasket correctly and align it with the bolt holes. Do not use sealant unless specified by the engine or gasket service instructions.
- Reinstall the exhaust elbow and tighten the fasteners in a crossing pattern to the manufacturer’s recommended torque specifications.
- Restore the cooling system, reconnect the battery, and run the engine while checking the joint for leaks.
Troubleshooting & FAQ
What are the signs of a failing exhaust elbow gasket?
Common signs include water leaks or rust trails at the joint between the exhaust elbow and manifold or riser, steam in the engine compartment, unexplained coolant loss, or engine overheating. A damaged gasket can also allow water to enter areas where it may cause serious engine damage.
Is sealant required when installing this gasket?
The gasket is generally installed dry after both mating surfaces have been cleaned. Do not apply sealant unless it is specifically required by the engine service information or the gasket manufacturer’s instructions.
When should the gasket be replaced?
Replace the gasket whenever the exhaust elbow is removed for service. Inspect the joint during routine maintenance for leakage, corrosion, deterioration, or signs that the gasket has shifted.
Will this gasket fit a closed cooling system?
The listed application is for standard cooling systems. For some older GM V8 small-block applications, the listing specifically indicates standard cooling only. Confirm the cooling-system type and exhaust configuration before ordering.
Is this an OEM component?
No. This listing is for an aftermarket replacement gasket. The part-number references above are provided for comparison and application checking.
Safety & Important Information
- Confirm the engine model, year, horsepower, stroke, cooling-system type, and exhaust configuration before purchase.
- Compare the replacement gasket with the original part, including its outline, openings, and bolt-hole pattern.
- Do not operate the engine if the exhaust joint leaks after installation.
- Professional installation is recommended when the exhaust elbow or cooling system is difficult to access.
- This is an aftermarket replacement, not an OEM component.
About Sea Sierra
- Marine replacement parts — Replacement components for selected sterndrive and inboard applications.
- Application-focused listings — Product references and fitment details are provided to help customers compare the original part.
- Support before installation — Review the model, year, cooling system, and original-part details before fitting a replacement.
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