When your boat’s exhaust bellows wear out, water can seep into places it shouldn’t, leading to costly damage. Replacing them promptly is key to keeping your sterndrive reliable and your time on the water stress-free.
This guide reviews ten top-rated exhaust bellows and tools, helping you choose the right fit for your MerCruiser or other marine engine. From direct replacements to expander tools, you’ll find options that match your needs and budget.
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UANOFCN 18654A1 Exhaust Bellow for Mercruiser SternDrive Alpha 1 Gen 2
Best forVersatile MerCruiser replacement
- Wide model compatibility
- Direct OEM replacement
ConsiderCheck fit for older models
Exhaust Bellows Expander Tool 91-45497A1 Fit for Mercruiser Alpha Gen One 1…
Best forQuick bellow installation
- Saves installation time
- Fits multiple drive models
ConsiderOnly for exhaust bellows
Quicksilver 8M0124227 Bell Housing Exhaust Bellows with Stainless Steel Cla…
Best forOEM-grade replacement
- Includes stainless clamps
- OEM specifications
ConsiderLimited to select models
SUISFLXGRO 3.0" ID Exhaust Flex Bellows, 100% Stainless SS304, 4.0" LONG Fl…
Best forHigh-heat exhaust systems
- Stainless SS304 material
- Handles extreme heat
ConsiderRequires welding
91-45497A1 Exhaust Bellows Expander Tool for MerCruiser Drives, Fits MC-1, …
Best forComfortable DIY installations
- Ergonomic grip
- Durable marine-grade build
ConsiderSpecific to MerCruiser
GHmarine 70981A3 3-4" Upper Exhaust Hose Bellow for MerCruiser Stern Drive …
Best forUpper exhaust connections
- Broad engine compatibility
- Includes SS316 clamps
ConsiderSpecific riser requirements
UANOFCN 30-803099T1 Transom Seal Bellows Kit for MerCruiser Alpha 1 Gen 2
Best forComplete transom service
- All-in-one kit
- Includes gimbal bearing
ConsiderLimited to Alpha 1 Gen 2
32734A3 Exhaust Bellows for Mercruiser Alpha 1 Gen 2 & Bravo 18654A1
Best forBudget-friendly replacement
- Includes clamps and clips
- Easy DIY installation
ConsiderLimited to listed models
MerCruiser Alpha Gen 1 & 2 Bravo 1 2 3 Exhaust bellows bellow boot 18654A1
Best forSimple direct replacement
- Direct fit for common drives
- Aftermarket cost savings
ConsiderLimited information
UANOFCN 4" Exhaust Bellow Water Shutter Kit for MerCruiser GM V6 V8 Engine
Best forFull exhaust kit replacement
- Includes shutters and boots
- OEM spec compliance
ConsiderLimited to specific engines
UANOFCN 18654A1 Exhaust Bellow – Reliable MerCruiser Fit
Brand: UANOFCN
A solid, versatile replacement for many MerCruiser stern drives.
This exhaust bellow from UANOFCN is designed specifically for MerCruiser Alpha 1 Gen 2 stern drives, replacing part numbers 18654A1, 32734A3, and 32734. It fits a wide range of models including #1, R, MR, TRS, Alpha I, Gen II, Bravo I, II, III, and Blackhawk, making it a versatile choice for many boat owners.
It also covers older MerCruiser engines like the 120/140 (1978-1982), 165 (1978-1981), 260 (1978-1982), and 470 (1978-1982). If you need a straightforward replacement that matches OEM specs, this bellow offers dependable performance without the hassle of modifications.
- Wide model compatibility
- Direct OEM replacement
- Durable rubber construction
- Check fit for older models
- Clamps not included
Yoursme Exhaust Bellows Expander Tool – Easy Install
Brand: Yoursme
A must-have tool for anyone replacing exhaust bellows regularly.
Struggling to stretch a new exhaust bellow over the housing? The Yoursme expander tool solves that problem. It fits MerCruiser Alpha One Gen I and Gen II, plus Bravo 1, 2, and 3 drives, along with Blackhawk, MC-1, and R-MR models. It replaces part numbers 91-45497A1, 90360, and Sierra 18-9847.
Made from superior steel, this tool is built to withstand the rigors of marine work. Its design lets you expand the bellow quickly, cutting installation time from hours to minutes. Whether you’re a pro or a DIYer, this tool makes the job far less frustrating.
- Saves installation time
- Fits multiple drive models
- Sturdy steel construction
- Only for exhaust bellows
- Requires some strength
Quicksilver 8M0124227 Bell Housing Exhaust Bellow – OEM Quality
Quicksilver is a trusted name in marine parts, and this exhaust bellow lives up to that reputation. It’s designed for select MerCruiser sterndrives and comes with stainless steel hose clamps at each end, so you have everything you need for a secure fit.
The bellow is flexible and durable, made to meet Mercury Marine’s original equipment specifications. Installation is straightforward with common tools, making it a great choice for boat owners who prefer to do their own maintenance. If you want peace of mind from an OEM-grade part, this is it.
- Includes stainless clamps
- OEM specifications
- Easy installation
- Limited to select models
- Premium price
SUISFLXGRO 3.0 Stainless Flex Bellow – High-Temp Solution
Brand: SUISFLXGRO
A durable flex bellow for demanding high-temperature environments.
For high-temperature exhaust applications, the SUISFLXGRO flex bellow is a standout. Made from 100% stainless steel SS304, it can handle short-term exposure up to 925°C (1700°F) and maintain stable performance over time. The 2-ply design with a leak-proof lining reduces vibration and noise while extending service life.
Installation is simple: just weld it on without any modifications. However, note that this is not for the front section near the engine or turbo, where temps can spike past 1000°C. It’s ideal for mid-exhaust sections where flexibility and heat resistance are critical.
- Stainless SS304 material
- Handles extreme heat
- Leak-proof design
- Requires welding
- Not for front exhaust
Bzcovac Exhaust Bellows Expander Tool – Ergonomic Choice
Another excellent expander tool, the Bzcovac model is designed for MerCruiser MC-1, R, MR, Alpha One, and other drives. It’s crafted with precision from high-quality materials to withstand harsh marine conditions, ensuring long-term durability.
The ergonomic design provides a comfortable grip, reducing hand fatigue during extended use. Whether you’re a professional mechanic or a weekend DIYer, this tool offers precise control for a secure installation. It’s a practical addition to any boat tool kit.
- Ergonomic grip
- Durable marine-grade build
- Versatile fit
- Specific to MerCruiser
- May be overkill for one-time use
GHmarine Upper Exhaust Hose Bellow – Engine Versatility
Brand: GHmarine
A dependable upper exhaust bellow for many MerCruiser engines.
The GHmarine upper exhaust bellow is a versatile option for various MerCruiser engines, including 3.0, 4.3, 5.0, and 5.7L V6 and V8 models. It fits manifolds from the 1980s and newer, covering a wide range of setups. The kit includes two SS316 clamps for a secure fit.
It replaces MerCruiser 70981A3, Sierra 18-2762, and other aftermarket part numbers. Designed for 3-inch 15-degree center-mounted risers with 4-inch elbows, this bellow is a practical choice for many boat owners looking for a reliable upper exhaust connection.
- Broad engine compatibility
- Includes SS316 clamps
- Replaces multiple part numbers
- Specific riser requirements
- Not for all drive types
UANOFCN Transom Seal Bellows Kit – Complete Service Kit
If you need a comprehensive solution, the UANOFCN transom seal bellows kit has you covered. It’s designed for MerCruiser Alpha 1 Gen 2 sterndrives from 1991-2002, with serial numbers 0D469859 and up. The kit includes exhaust bellow, shift cable bellows, drive bellows, gimbal bearing, bell housing gasket, O-ring, outdrive mounting gasket, water intake hose, and hose clamp.
This all-in-one kit replaces MerCruiser 803099T1 and other part numbers, making it a convenient way to handle multiple wear items at once. If you’re doing a full service, this kit saves time and ensures you have the right parts.
- All-in-one kit
- Includes gimbal bearing
- OEM replacement parts
- Limited to Alpha 1 Gen 2
- May include unneeded parts
NorthBoat 32734A3 Exhaust Bellow – Simple Replacement
The NorthBoat exhaust bellow is compatible with MerCruiser models including #1, R, MR, TRS, Alpha I, Gen II, Bravo I/II/III, and Blackhawk. It comes with two clamps and two clips, so you have everything needed for installation.
The replacement process is straightforward and can be done with common household tools. Made from high-quality materials and rigorously tested, this bellow promises long-lasting performance. It’s a budget-friendly option that doesn’t compromise on reliability.
- Includes clamps and clips
- Easy DIY installation
- Tested for durability
- Limited to listed models
- No brand reputation
mariine aftermarket Exhaust Bellow – Direct Fit Option
Brand: mariine aftermarket
A no-frills replacement bellow for standard MerCruiser setups.
This exhaust bellow from mariine aftermarket is designed to fit MerCruiser Alpha Gen 1 and Gen 2, as well as Bravo 1, 2, and 3 drives. It replaces part number 18654A1, making it a direct replacement for many popular models.
While the listing doesn’t provide extensive details, it’s marketed as a reliable aftermarket option. If you’re looking for a straightforward replacement without extra features, this could be a suitable choice. Just ensure it matches your specific drive model before purchasing.
- Direct fit for common drives
- Aftermarket cost savings
- Simple design
- Limited information
- No clamps included
UANOFCN 4-inch Exhaust Bellow Kit – Complete Shutter Set
The UANOFCN 4-inch exhaust bellow kit is a comprehensive set for MerCruiser GM V6 and V8 engines. It includes two water shutters/flappers (807166A1), two upper boots bellows (32-44348), and two lower boots bellows (32-14358), along with eight SS316 clamps.
This kit meets OEM specifications and is compatible with 7-degree and 14-degree dry joint systems from 2002-2010. If you need to replace the entire exhaust bellows and shutters, this kit provides everything in one package, saving you time and ensuring compatibility.
- Includes shutters and boots
- OEM spec compliance
- Eight stainless clamps
- Limited to specific engines
- May be more than needed
Buyer’s Guide: What to Consider
Choosing the right exhaust bellow involves several factors. Here are key points to consider when making your selection.
- Compatibility: Ensure the bellow fits your specific MerCruiser model and year. Check for part numbers like 18654A1 or 32734A3 and verify your drive type (Alpha, Bravo, etc.).
- Material Quality: Look for durable rubber or stainless steel options. Stainless steel resists high heat, while quality rubber offers flexibility and longevity in marine environments.
- Included Accessories: Some bellows come with clamps, clips, or even complete kits. Consider whether you need extra parts to avoid additional purchases.
- Ease of Installation: If you're a DIYer, choose bellows with simple installation or invest in an expander tool. Some kits are designed for quick fitting with common tools.
- Heat Resistance: For high-temperature areas, select stainless steel bellows that can withstand extreme heat. Rubber bellows are fine for standard exhaust sections but not near the engine.
Conclusion
Replacing your exhaust bellows is a critical maintenance task that prevents water intrusion and keeps your boat performing well. The options above range from direct replacements to complete kits and tools, so you can find what fits your needs and skill level.
For most MerCruiser owners, the Quicksilver bellow offers OEM quality, while the UANOFCN kits provide comprehensive solutions. If you’re tackling the job yourself, an expander tool like the Yoursme or Bzcovac models will save you time and effort.
Erica Steven is the founder and lead writer of WorstBrands, a site dedicated to providing honest and trustworthy reviews about outdoor gear and fashion products.
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