Mercury Marine Exhaust Elbow Gasket – Fits MerCruiser V8 Engines (Replaces 27-48042)

$5.99

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Product Details

This is a high-quality aftermarket Mercury Marine Exhaust Elbow Gasket designed for the exhaust elbow-to-manifold connection on a wide range of MerCruiser GM V8 engines, including 305, 327, 350, 427, 454, and 482 CID models from 1968 to 1986. It provides a reliable seal for raw water cooled (RWC) systems.

This part directly replaces Mercury Marine 27-48042, Sierra Marine 18-0885, and Barr Marine MC47-27-48042, ensuring broad compatibility for maintenance and repairs.

Installation Type: Bolt-on with a rectangular pattern.
Engine Application: Designed for select MerCruiser GM V8 gasoline engines.
Cooling System: Compatible with Raw Water Cooled (RWC) systems.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket brands.

Brand	Part Number
Mercury Marine	27-48042
Sierra Marine	18-0885
Barr Marine	MC47-27-48042

Engine & Model Compatibility

Confirm your engine model and year in the table below to ensure accurate fitment.

This gasket fits a variety of V8 engines under the Mercury MerCruiser brand. Please check your model and serial number against the listed ranges.

Model	Engine	Rated HP	Stroke	Years	OEM Part No.	Notes
198 MIE	GM 305 V8	198	4-Stroke	1977	27-48042	Serial Range: 4776402–4931099
225	GM 327 V8	225	4-Stroke	1968–1969	27-48042	Serial Range: 2399398–2694014
225 MIE	GM 327 V8	225	4-Stroke	1968–1969	27-48042	Serial Range: 2399398–2694014
228	GM 305 V8	228	4-Stroke	1977–1982	27-48042	Serial Range: 4765100–6218461
228 MIE	GM 305 V8	228	4-Stroke	1977–1980	27-48042	Serial Range: 4765100–5907057
228 TR	GM 305 V8	228	4-Stroke	1977	27-48042	Serial Range: 4765100–4888929
250	GM 327 V8	250	4-Stroke	1968–1969	27-48042	Serial Range: 2314301–2639854
250	GM 350 V8	250	4-Stroke	1977	27-48042	Serial Range: 4768000–4908849
250 MIE	GM 327 V8	250	4-Stroke	1968–1969	27-48042	Serial Range: 2314301–2639854
255	GM 350 V8	255	4-Stroke	1975–1976	27-48042	Serial Range: 4175500–4499060
255 MIE	GM 350 V8	255	4-Stroke	1975–1976	27-48042	Serial Range: 4175500–4499060
270	GM 350 V8	270	4-Stroke	1969–1972	27-48042	Serial Range: 2851074–3385720
270 MIE	GM 350 V8	270	4-Stroke	1969–1972	27-48042	Serial Range: 2851074–3077735
280 TRS	GM 350 V8	280	4-Stroke	1975–1976	27-48042	Serial Range: 4176250–4770199
300 TEMPEST	GM 350 V8	300	4-Stroke	1985–1986	27-48042	Serial Range: 6668677–0B430367
325	GM 427 V8	325	4-Stroke	1968–1974	27-48042	Serial Range: 2313965–3780449
325 MIE	GM 427 V8	325	4-Stroke	1968–1974	27-48042	Serial Range: 2313965–3780449
330	GM 454 V8	330	4-Stroke	1977–1981	27-48042	Serial Range: 4623115–6083144
330 MIE	GM 454 V8	330	4-Stroke	1977–1981	27-48042	Serial Range: 4623115–6083144
350 MIE	GM 454 V8	350	4-Stroke	1974–1976	27-48042	Serial Range: 3780450–4623109
370 TRS	GM 454 V8	370	4-Stroke	1978–1985	27-48042	Serial Range: 4179554–6721527
390	GM 482 V8	390	4-Stroke	1969–1970	27-48042	Serial Range: 2781129–2825059
390 MIE	GM 482 V8	390	4-Stroke	1969–1970	27-48042	Serial Range: 2781129–2825059
400 TRS	GM 454 V8	400	4-Stroke	1980–1986	27-48042	Serial Range: 4179554–0B457644
440 TRS	GM 454 V8	440	4-Stroke	1983–1986	27-48042	Serial Range: 4179554–0B485220
460 TRS	GM 482 V8	460	4-Stroke	1983–1986	27-48042	Serial Range: 4179554–6181046
898	GM 305 V8		4-Stroke	1977–1982	27-48042	Serial Range: 4762210–6218461

Technical Specs

Product Type: Exhaust Elbow Gasket
Connection: Exhaust Elbow to Manifold
Application: Raw Water Cooled (RWC) systems
Fuel Type: Gasoline
Material: Composite
Bolt Pattern: Rectangular
Bolt Centers: 2-3/4" x 4-1/2"
Product Dimensions: 6.0" H x 11.25" W x 1.25" L
OEM Reference: Mercury Marine 27-48042

What’s in the Box

Package contents may vary based on the brand selected:

1 x Exhaust Elbow Gasket (Mercury OEM equivalent)
2 x Exhaust Elbow Gaskets (Barr Marine equivalent)

Installation Notes

Ensure the engine is completely cool before beginning work.
Disconnect the battery to prevent accidental starting.
Drain the engine block and exhaust manifold of water.
Carefully remove the exhaust hose connected to the elbow.
Unbolt and remove the exhaust elbow from the manifold. Note the orientation of the bolts.
Thoroughly clean both mating surfaces of the manifold and elbow, removing all old gasket material and corrosion.
Place the new gasket onto the manifold, aligning the bolt holes. Do not use any sealant unless specified by the engine manufacturer.
Reinstall the exhaust elbow and tighten the bolts to the manufacturer's recommended torque specifications and sequence.
Reconnect the exhaust hose and any other disconnected components.
Reconnect the battery, refill the cooling system, and check for leaks after starting the engine.

Troubleshooting & FAQ

How do I know if this gasket will fit my MerCruiser engine?

The best way is to verify your engine model and serial number against the compatibility table provided on this page. This gasket is designed for specific MerCruiser GM V8 engines from 1968–1986. Always cross-reference the OEM part number (27-48042) with your service manual.

What are the signs of a bad exhaust elbow gasket?

Common symptoms include water leaking externally from the joint between the elbow and manifold, steam or water in the engine bay, engine overheating, or in severe cases, water intrusion into the engine cylinders (hydrolock). Visual inspection for rust streaks or water drips around the gasket area is a key indicator.

Is this gasket for raw water or freshwater cooled systems?

This gasket is specified for use in Raw Water Cooled (RWC) systems, where seawater or lake water circulates directly through the engine and exhaust components.

How often should this gasket be replaced?

Replacement interval depends on usage and environment (saltwater vs. freshwater). It's typically recommended to inspect exhaust components annually and replace gaskets whenever the exhaust elbow or manifold is removed for service or inspection, or every 3-5 years as preventative maintenance in saltwater environments.

Can I reuse my old bolts when installing the new gasket?

It is strongly recommended to use new bolts, especially if the old ones show any signs of corrosion, rust, or thread damage. Corroded bolts may not torque correctly, leading to a poor seal and potential leaks.

The package from one brand has two gaskets, but I only need one. Why?

Some V8 engines require two exhaust elbows, one for each cylinder bank. Aftermarket brands like Barr Marine often package gaskets in pairs for convenience, allowing you to service both sides of the engine at once.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

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