27-18272 Exhaust Elbow Gasket for MerCruiser 3.7L 4-Cylinder

SERDAMARINE / MARINE EXHAUST PARTS

Exhaust Elbow Gasket for MerCruiser 3.7L 4-Cylinder Applications

This exhaust elbow mounting gasket (referenced to OEM 27-18272) seals the exhaust elbow mounting joint on specified MerCruiser 4-cylinder stern drive applications, including 3.7L and 3.7LX MCM (224 CID) models. Fitment depends on whether the engine is equipped with an aluminum manifold (1985–1989 170/470) or a cast iron manifold (excluding 1976–1982 470), and this listing is for the gasket item rather than the exhaust elbow assembly.

Engine Applications

This gasket fits specified MerCruiser 4-cylinder exhaust manifold and elbow assemblies. Because 3.7L engines used different manifold designs across production years, do not select the gasket by displacement alone; match the engine model, year, installed manifold version (aluminum or cast iron), and gasket reference against your actual assembly.

• MerCruiser 3.7L 4-Cylinder 170 / 470 — Years: 1985–1989. Configuration: With aluminum exhaust manifold. Fits when specified
• MerCruiser 4-Cylinder Engines — Configuration: With cast iron exhaust manifold. Excludes 1976–1982 model 470. Fits when specified
• MerCruiser 3.7L & 3.7LX MCM (224 CID) 4-Cylinder — Models 165, 170, 180, 190, 470, 485, 488 — Years: 1980–1989. General manifold, elbow, end-cap, and gasket series grouping; verify installed manifold material (1985–1989 aluminum on 170/470, or cast iron excluding 1976–1982 470) and exact elbow mounting gasket number. Fits when specified

Not Suitable For

• MerCruiser 470 (4-Cylinder) — Years: 1976–1982. Excluded under cast iron manifold applications. Not suitable

Additional model-specific applications

• MerCruiser-built 4-cylinder engines, 1985, cast-iron exhaust manifold.

Reference Numbers

The numbers below are public references for part identification and do not by themselves guarantee interchangeability across every manifold version or indicate original manufacturer identity. Keep Sierra references 18-0881 and 18-0881-1 distinct when cross-checking part numbers.

Supplied Parts

• Exhaust elbow gasket

Service & Installation Notes

General service guidance only. Use the service manual for your exact engine and exhaust configuration.

1. Shut down the engine, disconnect the starting circuit to prevent accidental cranking, and allow the exhaust manifold and elbow to cool completely before servicing.
2. Support the exhaust elbow while removing the mounting fasteners so its weight does not damage the mating surfaces or connected exhaust components.
3. Clean both the manifold and elbow mounting faces thoroughly, removing old gasket material and corrosion while protecting the sealing surfaces from gouges.
4. Compare the new gasket profile and port openings directly against the manifold and elbow joint, then assemble and tighten fasteners according to the factory service manual for your specific manifold version.
5. After installation, inspect the joint during initial operation; if any exhaust or sealing abnormality is present, stop the engine immediately and recheck the assembly.

The Serdamarine Approach

Exhaust parts need a configuration match. Serdamarine focuses on marine exhaust manifolds and their related service parts. Application details, connection requirements and public reference numbers are presented together to support part selection.

Questions Before Replacement