Exhaust Bellows – Fits Mercruiser Alpha One & Bravo Drives (Replaces 18654A1, 32734A3)
Exhaust Bellows – Fits Mercruiser Alpha One & Bravo Drives (Replaces 18654A1, 32734A3) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Exhaust Bellows – Fits Mercruiser Alpha One & Bravo Drives (Rep...
Exhaust Bellows – Fits Mercruiser Alpha One & Bravo Drives (Replaces 18654A1, 32734A3) is backordered and will ship as soon as it is back in stock.
Product Details
This high-quality Exhaust Bellows is designed for a broad range of Mercruiser stern drives, including Alpha One Gen I (1983–1990), Alpha One Gen II (1991–Current), and Bravo I, II, & III models. It is also compatible with #1, R, MR, TRS, and Blackhawk drives from 1978 onward, providing a reliable replacement for your vessel's exhaust system.
This part serves as a direct replacement and provides interchange for Mercury 18654A1, 32734A3, 18654B1, 8M0124227; Sierra 18-2750; GLM 89100; and CEF 500512K.
- Engineered as a direct replacement for a precise fit.
- Secured with included stainless steel hose clamps for lasting durability.
- Kit includes one bellows and two clamps for a complete installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By |
|---|---|---|
| Mercury | 18654A1 | 8M0124227 |
| Mercury | 32734A3 | |
| Mercury | 18654B1 | |
| Mercury | 8M0124227 | |
| Sierra | 18-2750 | |
| GLM | 89100 | |
| CEF | 500512K |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercruiser applications, this part covers a wide range of models from 1978 to current, as detailed in the matrix.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Mercruiser | 120/140 | 120-140 | 4-Stroke | 1978–1982 | 18654A1/8M0124227 |
| Mercruiser | 165 | 165 | 4-Stroke | 1978–1981 | 18654A1/8M0124227 |
| Mercruiser | 260 | 260 | 4-Stroke | 1978–1982 | 18654A1/8M0124227 |
| Mercruiser | 470 | 470 | 4-Stroke | 1978–1982 | 18654A1/8M0124227 |
| Mercruiser | 485 | 485 | 4-Stroke | 1980–1982 | 18654A1/8M0124227 |
| Mercruiser | 898/228 | 228 | 4-Stroke | 1978–1982 | 18654A1/8M0124227 |
| Mercruiser | Alpha One Gen I | Various | 4-Stroke | 1983–1990 | 18654A1/8M0124227 |
| Mercruiser | Alpha One Gen II | Various | 4-Stroke | 1991–Current | 18654A1/8M0124227 |
Technical Specs
- Product Type
- Exhaust Bellows / Bellow
- Installation
- Direct replacement
- Connection
- Hose clamp secured
- Housing Material
- Rubber
- Housing Color
- Black
- Dimensions
- Inner Diameter: 2.5 in (63.5 mm), Length: 5.25 in (133.4 mm)
- Fitting Type
- Exhaust bellows with clamps
- Warranty
- Varies by seller (1 year typical)
- Other Technical Attributes
- For use on MerCruiser MC-I, MR, Alpha One, Alpha One Gen II, Vazer, Bravo and Blackhawk (1963 and newer) stern drives
What’s in the Box
- 1 x Exhaust Bellow (replaces 18654A1/8M0124227)
- 2 x Stainless Steel Hose Clamps
Installation Notes
- Ensure the engine is off and disconnect the battery for safety.
- Tilt the sterndrive unit to the full upward or trailer position to access the bellows.
- Loosen and remove the hose clamps securing the old exhaust bellows.
- Carefully remove the old bellows from the transom assembly and drive.
- Thoroughly clean the mounting surfaces on both ends to ensure a clean, secure seal.
- Slide the new hose clamps over each end of the new bellows before installation.
- Fit the new exhaust bellows into position, ensuring it is fully seated on the drive and transom assembly.
- Position and securely tighten the new hose clamps to prevent leaks.
- Lower the sterndrive and visually inspect for proper alignment and a tight fit.
- After reconnecting the battery, run the engine and check for any exhaust leaks around the new bellows.
Troubleshooting & FAQ
How do I know if this exhaust bellows will fit my drive?
This part is designed for a wide range of Mercruiser drives. Please review the 'Engine & Model Compatibility' and 'Part Number Matrix' sections on this page to confirm that your specific model and original part number are listed.
What are the signs that my exhaust bellows needs replacement?
Common signs of a failing exhaust bellows include visible cracks, splits, or perishing of the rubber. You might also notice an unusually loud exhaust noise or find water in the bilge area, which can indicate a leak.
How often should I inspect or replace my exhaust bellows?
It is recommended to inspect all bellows annually as part of routine maintenance. For preventative care, consider replacement every 3-5 years, depending on usage, storage conditions (sun and heat exposure), and water type (saltwater vs. freshwater).
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.
Payment & Security
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