27-18272 Exhaust Manifold Riser Gasket for Mercruiser 3.7L | JLM Marine

Exhaust Manifold Riser Gasket for MerCruiser 3.7L – Replaces 27-18272

This Exhaust Manifold Riser Gasket is designed for MerCruiser 4-cylinder 3.7L (224 cid) marine engines, including 165, 170, 180, and 190 HP models from 1985–1989. It provides a reliable seal between the exhaust manifold and riser elbow to prevent exhaust leaks and maintain engine performance.

Direct replacement for MerCruiser OEM #27-18272 and #27-97863, as well as Sierra #18-0881. This aftermarket gasket is manufactured to OEM specifications for reliable fit and durability.

• Compatible with MerCruiser 3.7L (224 cid) 4-cylinder engines
• Replaces multiple OEM and aftermarket part numbers
• Essential component for exhaust system maintenance

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

This package includes:

• 1× Exhaust Manifold Riser Gasket

Installation Guide

1. Ensure the engine is cool and disconnect the battery before starting work.
2. Remove the exhaust riser elbow from the manifold, taking care to retain all mounting hardware.
3. Thoroughly clean both the manifold and riser mating surfaces, removing all old gasket material and carbon deposits.
4. Inspect both surfaces for cracks, warping, or corrosion that may prevent a proper seal.
5. Position the new gasket on the manifold, aligning all bolt holes carefully.
6. Install the riser elbow onto the manifold with the gasket in place.
7. Hand-tighten all mounting bolts in a star or cross pattern to ensure even alignment.
8. Torque the bolts to manufacturer specifications (consult your service manual for proper torque values).
9. Reconnect the battery and start the engine.
10. Inspect the gasket area for exhaust leaks while the engine is running. Listen for hissing sounds and check for visible exhaust escaping.
11. Allow the engine to reach operating temperature and recheck for leaks.
12. If leaks are detected, shut down the engine, allow it to cool, and recheck bolt torque and gasket alignment.

Troubleshooting & FAQ

Q: How do I confirm this gasket fits my MerCruiser engine?
A: Check the compatibility table above for your engine model, horsepower rating, year, and serial number range. Verify that your original gasket matches the dimensions and bolt pattern shown in the product images.

Q: How often should I replace the exhaust manifold riser gasket?
A: Replace the gasket whenever you remove the riser elbow for service or repair. Also replace if you notice exhaust leaks, corrosion, or deterioration of the gasket material during routine inspection.

Q: What are the signs of a failing exhaust gasket?
A: Common symptoms include hissing or ticking noises from the exhaust area, visible exhaust leaks, decreased engine performance, and corrosion around the gasket area. Address leaks immediately to prevent damage to surrounding components.

Q: Can I reuse the old gasket if it looks okay?
A: No, exhaust gaskets are designed for one-time use. Reusing a gasket—even if it appears intact—can result in poor sealing, exhaust leaks, and potential engine damage.

Q: Is this an OEM or aftermarket gasket?
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.