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)

This high-quality exhaust elbow gasket is engineered for a precise fit on a range of MerCruiser sterndrive and inboard engines. It is designed for 120 series (1983 and newer), 140/3.0L, 470, 165 inline 6-cylinder, GM V-8 small block models (1982 and older) with standard cooling, and Ford V-8 engines.

This component serves as a direct replacement for multiple OEM and aftermarket part numbers, including 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 Type: Bolt-on
• Connection Point: Between exhaust manifold/riser and elbow
• Included in Package: One exhaust elbow gasket

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Exhaust Elbow Gasket (27-99777-2)

Installation Guide

1. Safety First: Disconnect the battery terminals and allow the engine to cool completely.
2. Drain Coolant: Drain the engine coolant from the exhaust manifold to a level below the elbow.
3. Remove Components: Carefully detach any hoses connected to the exhaust elbow. Loosen and remove the bolts securing the elbow to the manifold/riser.
4. Remove Old Gasket: Gently pry the elbow off and remove the old gasket.
5. Clean Surfaces: Thoroughly clean both mating surfaces on the elbow and the manifold. Ensure they are free of old gasket material, rust, or debris.
6. Install New Gasket: Position the new gasket correctly, aligning it with the bolt holes. Do not use any sealant unless specified by the manufacturer.
7. Reassemble: Reattach the exhaust elbow and tighten the bolts to the manufacturer's recommended torque specifications in a star or crisscross pattern.
8. Final Checks: Reconnect all hoses and refill the cooling system. Start the engine and carefully check for any exhaust or coolant leaks around the gasket area.

Troubleshooting & FAQ

How do I confirm this fits my engine?
Start by checking the Compatible Engine Models table on this page. Cross-reference your engine's model, year, and serial number. You can also use the Part Number Cross-Reference table to see if your old gasket's part number matches one of the listed equivalents.

What are the signs of a failing exhaust elbow gasket?
Common symptoms include visible water leaks or rust stains around the joint between the exhaust elbow and manifold, engine overheating, or an unusual amount of steam from the engine compartment. Internal leaks can also allow water to enter the engine cylinders, causing significant damage.

How often should I replace the exhaust elbow gasket?
It is recommended to replace the exhaust elbow gasket whenever the exhaust elbow or manifold is removed for service or inspection. In saltwater environments, it's good practice to inspect these components every few years for corrosion and replace gaskets as a preventative measure.

OEM vs. Aftermarket?
This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?
We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?
This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.