Upper Exhaust Bellows for MerCruiser 3.0L–8.2L Sterndrives — Replaces 70981A3
Upper Exhaust Bellows for MerCruiser 3.0L–8.2L Sterndrives — Replaces 70981A3 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Upper Exhaust Bellows for MerCruiser 3.0L–8.2L Sterndrives — Replac...
Upper Exhaust Bellows for MerCruiser 3.0L–8.2L Sterndrives — Replaces 70981A3 is backordered and will ship as soon as it is back in stock.
Product Details
This replacement upper exhaust bellows is intended for selected MerCruiser sterndrive applications using 3.0L through 8.2L engines. It is designed to connect compatible exhaust riser and elbow assemblies and should be matched to the original bellows, connection dimensions, engine model, and sterndrive configuration before ordering.
This bellows is listed as a replacement for MerCruiser 70981A3. Additional aftermarket reference numbers commonly associated with this application include Sierra 18-2762, GLM 89070, and Mallory Marine 9-72808. Reference numbers are provided for identification and should be verified against the application and original part.
- Upper exhaust bellows for compatible MerCruiser sterndrive exhaust systems.
- Designed for applications using 3-inch, 15-degree center-mounted risers with a 4-inch elbow.
- Durable reinforced rubber construction for marine exhaust-system service.
- Single replacement bellows; clamps and other installation hardware are not included unless separately specified.
Part Number Matrix
Use the following references to help identify the replacement part. Confirm dimensions and application details before installation.
| Brand | Part Number |
|---|---|
| MerCruiser | 70981A3 |
| Sierra | 18-2762 |
| GLM | 89070 |
| Mallory Marine | 9-72808 |
Engine & Model Compatibility
The application range below is a reference for commonly listed MerCruiser configurations. Exact fitment can vary by model year, exhaust-manifold and riser arrangement, sterndrive configuration, and serial-number range. Verify the original part number and connection dimensions before purchase.
| Brand | Model or Engine Family | Stroke | Commonly Listed Years | Reference Part No. | Application Notes |
|---|---|---|---|---|---|
| MerCruiser | 165, 170, 3.7L, 180, 190, 470, 485, 488 | 4-Stroke | 1980–1989 | 70981A3 | Verify the manifold, riser, and elbow arrangement. |
| MerCruiser | 3.0L | 4-Stroke | 1983 and later | 70981A3 | Confirm the original bellows and connection dimensions. |
| MerCruiser | V6 229/262 CID | 4-Stroke | 1983 and later | 70981A3 | Application depends on the exhaust configuration. |
| MerCruiser | 5.0L / 305 CID | 4-Stroke | 1983 and later | 70981A3 | Chevrolet-based V8 application; verify configuration. |
| MerCruiser | 5.7L / 350 CID | 4-Stroke | 1983 and later | 70981A3 | Chevrolet-based V8 application; verify configuration. |
| MerCruiser | 6.2L / 377 CID | 4-Stroke | 1983 and later | 70981A3 | Confirm the exhaust riser and elbow dimensions. |
| MerCruiser | 7.4L / 454 CID | 4-Stroke | 1981 and later | 70981A3 | Big-block application; verify the original part. |
| MerCruiser | 8.2L / 502 CID | 4-Stroke | 1981 and later | 70981A3 | Big-block application; verify the original part. |
Technical Specs
- Product Type
- Upper exhaust bellows
- Application
- Compatible MerCruiser sterndrive exhaust systems
- Material
- Reinforced rubber
- Connection
- Designed for compatible 3-inch riser to 4-inch elbow applications
- Riser Configuration
- 3-inch, 15-degree center-mounted riser application where specified
- Weight
- 198 g (0.44 lb)
What’s in the Box
- 1 x Upper exhaust bellows
Note: Clamps, sealant, and other installation hardware are not included unless separately stated in the order details.
Installation Notes
- Disconnect the boat battery and allow the engine and exhaust components to cool completely.
- Gain clear access to the exhaust riser and elbow assembly.
- Loosen and remove the clamps securing the existing exhaust bellows. Reuse them only if they are in suitable condition and are specified for reuse.
- Remove the old bellows and note its orientation before disposal.
- Clean the mating surfaces on the riser and elbow, removing debris and old sealant as appropriate.
- Compare the replacement bellows with the original part and confirm that the length, openings, angle, and orientation match.
- Fit the new bellows evenly over both mating surfaces.
- Install suitable clamps and tighten them according to the engine or sterndrive service procedure. Do not overtighten.
- After installation, run the engine in a safe environment and inspect for exhaust or water leaks.
- Reconnect the battery only after the installation and inspection are complete.
Troubleshooting & FAQ
How do I confirm whether this bellows fits my engine?
Compare the original bellows, replacement references, connection dimensions, riser angle, exhaust elbow, engine model, sterndrive configuration, and serial-number information. A listed engine family alone does not confirm every exhaust configuration.
What are common signs of a failing exhaust bellows?
Cracks, splits, hardening, water leakage, exhaust odor in the engine compartment, and overheating can indicate a damaged exhaust bellows. Inspect the part whenever the exhaust system is serviced.
How often should an exhaust bellows be inspected?
Inspect the bellows at least annually and whenever the vessel is serviced. Replace it immediately if it is cracked, brittle, split, deformed, or leaking. Saltwater exposure and storage conditions can accelerate deterioration.
Are clamps included?
No. This listing is for one upper exhaust bellows. Clamps and other installation hardware are not included unless separately specified.
What is the difference between an upper and lower exhaust bellows?
The upper exhaust bellows connects compatible exhaust riser and elbow components. A lower bellows is part of the transom and gimbal-housing assembly. Confirm which bellows your sterndrive requires before ordering.
Is this an OEM part?
This is an aftermarket replacement for the listed application. The MerCruiser and other brand numbers are reference numbers used to identify compatible replacement applications; this product is not represented as a genuine OEM MerCruiser part.
Shipping speed and cost?
Shipping methods, delivery estimates, and cost are shown at checkout based on the destination and service selected.
Warranty and returns?
Warranty and return eligibility are governed by the current store policies. Contact support with your order details if the product arrives damaged or an issue occurs during normal use.
Safety & Important Information
- Verify the original part, dimensions, engine model, sterndrive configuration, and exhaust arrangement before ordering.
- Do not operate the boat if exhaust gases or cooling water are leaking into the engine compartment or bilge.
- Follow the applicable manufacturer service procedure and use suitable clamps and hardware.
- Professional installation is recommended when access is restricted or the exhaust configuration is uncertain.
- This is an aftermarket replacement component, not a genuine OEM part.
About Sea Sierra
- Pro-Grade Standards — Marine replacement parts selected for dependable service in real-world conditions.
- Global Fulfillment — Shipping options and delivery estimates are provided during checkout.
- Manufacturer-Direct Value — Practical replacement solutions with clear application information.
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