Exhaust Manifold Riser Elbow Gasket – Fits MerCruiser 4.3L, 5.0L, 5.7L, 5.8L, 6.2L, 7.4L, 8.1L, 8.2L Engines (Replaces 030240, 18-2849-1, 27-818832, 27-863726)
Exhaust Manifold Riser Elbow Gasket – Fits MerCruiser 4.3L, 5.0L, 5.7L, 5.8L, 6.2L, 7.4L, 8.1L, 8.2L Engines (Replaces 030240, 18-2849-1, 27-818832, 27-863726) is backordered and will ship as soon as it is back in stock.
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Exhaust Manifold Riser Elbow Gasket – Fits MerCruiser 4.3L, 5.0L, 5...
Product Details
This Exhaust Manifold Riser Elbow Gasket is engineered for a precise fit on a wide range of MerCruiser engines from 1982 to 2002. It is compatible with V6 models like the 4.3L and V8 models including the 5.0L, 5.7L, 5.8L, 6.2L, 7.4L, 8.1L, and 8.2L, covering both carbureted, TBI, and MPI systems.
This part serves as a direct replacement for several part numbers, including Great Lakes Memories 030240, Sierra 18-2849-1, Mercury 27-818832, and Mercury 27-863726.
- Installs between the exhaust manifold and the exhaust riser in marine wet-joint exhaust systems.
- Features a durable stainless steel core that prevents distortion under high pressure.
- Coated on both sides with graphite for a superior seal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Great Lakes Memories | 030240 |
| Sierra | 18-2849-1 |
| Mercury | 27-818832 |
| Mercury | 27-863726 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This gasket fits the specified MerCruiser models from 1982–2002 using wet-joint exhaust systems. It is not compatible with dry-joint systems introduced after 2002.
| Model | Engine Type | Rated HP | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| 4.3L V6 | 262 CID V6 | Various | 1982–2002 | 030240 | Fits carbureted, TBI and MPI engines |
| 5.0L V8 | 305 CID V8 | Various | 1982–2002 | 030240 | Fits small block V8 engines |
| 5.7L V8 | 350 CID V8 | Various | 1982–2002 | 030240 | Fits small block V8 engines |
| 5.8L V8 | 351 CID V8 | Various | 1982–2002 | 030240 | Ford-based engines |
| 6.2L V8 | 377 CID V8 | Various | 1982–2002 | 030240 | Small block V8 engines |
| 7.4L V8 | 454 CID V8 | Various | 1982–2002 | 030240 | Big block V8 engines |
| 8.1L V8 | 496 CID V8 | Various | 1982–2002 | 030240 | Big block V8 engines |
| 8.2L V8 | 502 CID V8 | Various | 1982–2002 | 030240 | Big block V8 engines |
Technical Specs
- Product Type
- Exhaust Riser Gasket
- Installation
- Between manifold and exhaust riser
- Material
- Stainless Steel Core with Graphite Coating
- Application
- Marine wet-joint exhaust systems
- Fitment
- V6 and V8 engines (GM and Ford based)
- Dimensions
- 5 × 4 × 0.05 inches (127 × 102 × 1.27 mm)
- Weight
- 1.9 ounces (54 g)
- Manufacturer
- GLM Marine
What’s in the Box
- 1 x Exhaust Riser Gasket (030240)
Installation Notes
- Ensure the engine is completely cool and disconnect the negative battery terminal for safety.
- Drain the engine block and exhaust manifold cooling passages to prevent water spills.
- Carefully unbolt and remove the exhaust riser from the manifold. You may need to gently tap it with a rubber mallet to break the seal.
- Remove the old gasket. Thoroughly clean both mating surfaces on the manifold and riser, ensuring they are flat, clean, and free of any old material or corrosion.
- Position the new gasket on the manifold, aligning it with the bolt holes. Do not use any sealant.
- Reinstall the exhaust riser and tighten the bolts in a crisscross pattern to the manufacturer's specified torque.
- Refill the cooling system, reconnect the battery, and start the engine.
- Carefully inspect the riser-to-manifold joint for any signs of water or exhaust leaks.
Troubleshooting & FAQ
Does this gasket fit my specific engine?
This gasket fits most MerCruiser V6 and V8 engines (both GM and Ford-based) manufactured between 1982 and 2002. It is designed specifically for wet-joint exhaust systems. If your engine is newer than 2002, it may have a dry-joint system, and this gasket will not be compatible. Always confirm fitment using the detailed compatibility table.
What are the signs of a failed riser gasket?
Common symptoms of a bad exhaust riser gasket include external water leaks from the joint between the riser and manifold, rust stains originating from the joint, steam from the engine compartment, and, in severe cases, water entering the engine cylinders, which can lead to hydrostatic lock and catastrophic engine failure.
How often should this gasket be replaced?
It is recommended to inspect exhaust gaskets annually, especially in saltwater environments. They should be replaced whenever the riser or manifold is removed for service, or every 3-5 years as part of preventative maintenance to avoid leaks.
Do I need to use sealant with this gasket?
No. This gasket is designed to be installed dry. The graphite coating provides the necessary seal. Applying RTV or other sealants can interfere with its performance and may cause an improper seal or premature failure.
What is the difference between a wet-joint and dry-joint exhaust?
A wet-joint exhaust system, which this gasket is for, allows engine cooling water to pass through the gasket between the manifold and riser. A dry-joint system has a sealed-off water passage and uses a different type of gasket, preventing water from passing through the gasket joint itself. MerCruiser began switching to dry-joint systems around 2002.
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/specifications vs 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
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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