Exhaust Elbow Gasket – Fits MerCruiser 120 140 2.5L 3.0L V8 Models (Replaces 27-997771, Sierra 18-2833-9)

Exhaust Elbow Gasket – Fits MerCruiser 2.5L, 3.0L & V8 Models

This exhaust elbow gasket is designed for specific MerCruiser engines that use a wet-joint exhaust system. It provides a reliable seal between the exhaust manifold and the riser/elbow, preventing water and exhaust gas leaks. This kit is compatible with MerCruiser 2.5L & 3.0L I4 models from 1993 to current and older (1982 and earlier) GM V8 small block models.

This part is a direct replacement for MerCruiser part numbers 27-52076, 27-99777, 27-997771, 27-997772, and 27-99777B2. It also replaces Sierra 18-2833-9, Barr Marine MC472799777, GLM 31520, Mallory 9-61407, and Osco 52076.

• Installation Type: Designed for wet-joint exhaust systems.
• Material: Produced from high-quality composite fiber gasket material to ensure a durable seal.
• Package Includes: Four individual exhaust elbow gaskets to complete the job.

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.

Technical Specifications

Package Contents

• 4 x Exhaust Elbow Gasket (equivalent to 27-99777, 27-997771)

Installation Guide

1. Ensure the engine is completely cool and disconnect the negative battery terminal for safety.
2. Drain the engine coolant to a level below the exhaust manifold and riser connection.
3. Carefully loosen and remove the bolts securing the exhaust elbow or riser to the manifold.
4. Gently separate the components. You may need to lightly tap the elbow to break the seal.
5. Remove the old gasket and discard it.
6. Thoroughly clean both mating surfaces on the manifold and the elbow. Ensure they are completely free of old gasket material, rust, and corrosion.
7. Position the new gasket correctly on the manifold, aligning it with the bolt holes.
8. Re-attach the exhaust elbow, ensuring it sits flush against the new gasket.
9. Install and tighten the bolts in a crossing pattern to the manufacturer's recommended torque specifications to ensure even pressure.
10. Refill the cooling system, reconnect the battery, and start the engine. Carefully check the joint for any signs of water or exhaust leaks.

Troubleshooting & FAQ

How do I confirm this gasket fits my engine?
This gasket is designed for MerCruiser 2.5L and 3.0L I4 models from 1993-current and GM V8 small block models from 1982 and older that use a wet-joint exhaust system. The best way to confirm fitment is to check the "Compatible Engine Models" table and cross-reference your OEM part number. This part replaces MerCruiser 27-997771 and Sierra 18-2833-9, among others listed in the cross-reference table.

What are the signs that my exhaust elbow gasket has failed?
Common signs of a failed gasket include visible water leaking externally from the joint between the manifold and elbow, milky or discolored engine oil (indicating water intrusion), or steam coming from the engine compartment near the exhaust manifold.

How often should I replace my exhaust elbow gasket?
It is best practice to replace exhaust gaskets whenever the exhaust manifold or riser/elbow is removed for service or inspection. In saltwater applications, it is recommended to inspect the entire exhaust system every 3-5 years and replace gaskets as needed to prevent catastrophic failure.

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.