Full Flow Elbow Gasket – Fits MerCruiser GM V-6 & V-8 Stern Drives with Risers (Replaces 27-864547A02, 27-864547A1)

Full Flow Elbow Gasket – Fits MerCruiser GM V-6 & V-8 Stern Drives with Risers (Replaces 27-864547A02, 27-864547A1)

This full flow elbow gasket is designed for MerCruiser GM V-6 and V-8 engines (4.3L, 5.0L, 5.7L, 6.2L) manufactured from 2002 and newer. It is specifically intended for models equipped with a dry joint exhaust manifold and a standard cooling system that utilizes risers.

This part is a direct replacement for MerCruiser part numbers 27-864547A02 and 27-864547A1, as well as Sierra 18-0721. It ensures a precise fit and reliable seal to prevent exhaust and water leaks.

• Gasket Style: Full Flow (Open) gasket intended for standard cooling applications.
• Installation Type: Designed exclusively for dry joint exhaust systems that use risers.
• Included in Package: One high-grade metal 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.

Technical Specifications

Package Contents

• 1 x Riser Gasket (Open) (27-864547A02/27-864547A1)

Installation Guide

1. Ensure the engine is completely cool and the battery is disconnected.
2. Drain the engine coolant to a level below the exhaust manifold.
3. Carefully unbolt and remove the exhaust riser from the manifold.
4. Remove the old gasket and discard it responsibly.
5. Thoroughly clean both the manifold and riser mating surfaces. Ensure they are free of any old gasket material, carbon buildup, or corrosion.
6. Position the new full flow gasket onto the manifold, making sure it is correctly aligned with the bolt holes and passages.
7. Reinstall the exhaust riser, ensuring it sits evenly on the new gasket.
8. Tighten the riser bolts in a crisscross pattern to the manufacturer's recommended torque specifications.
9. Reconnect any hoses and refill the cooling system.
10. Start the engine and carefully inspect the riser-to-manifold joint for any signs of water or exhaust leaks.

Troubleshooting & FAQ

Q: How do I know if I need a "full flow" or "restrictor" gasket?

A: This full flow (open) gasket is for MerCruiser engines using a standard cooling system. Engines with a closed (freshwater) cooling system typically require a restrictor-style gasket to regulate water flow. Always verify your engine's cooling system requirements before ordering.

Q: Will this fit my MerCruiser engine if it's older than 2002?

A: No, this gasket is specifically designed for models from 2002 and newer that use the dry joint exhaust system. Pre-2002 engines typically use a different "wet joint" exhaust system and require a different gasket.

Q: What are the symptoms of a failing elbow gasket?

A: Common signs of a failed gasket include visible water leaks or drips from the joint between the manifold and riser, steam rising from the engine compartment, engine overheating alarms, or, in severe cases, evidence of water intrusion into the engine cylinders.

Q: OEM vs. Aftermarket?

A: 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.

Q: How fast do you ship and how much does it cost?

A: 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.

Q: What is your warranty and return policy?

A: 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.