mariine aftermarket MerCruiser exhaust bellows 18654A1 for Alpha Gen1/Gen2 & Bravo 1-3 — OEM-fit, oil- and saltwater-resistant

This is a direct-fit aftermarket exhaust bellows (bellow boot) by mariine aftermarket designed to replace MerCruiser Alpha Gen 1 & 2 and Bravo 1, 2, 3 exhaust bellows part 18654A1.

If you operate a sterndrive boat with a MerCruiser Alpha or Bravo lower unit, the exhaust bellows are a critical flexible connector that isolates engine vibrations, routes exhaust through the transom, and keeps seawater from entering the drive. The mariine aftermarket 18654A1 replacement is molded to match the original contour and mounting dimensions so you can restore a sealed, flexible exhaust pathway without modifying your drive or transom fairing.

How does this bellows restore a noisy or leaking exhaust?

Worn bellows often crack, split, or harden, causing exhaust leaks, increased engine noise, and potential water ingress. Installing a new 18654A1 bellows returns flexibility, reseals the joint between exhaust elbow and transom, and reduces vibration transfer into the hull.

• OEM-compatible shape for easy swap with Alpha Gen 1 & 2 and Bravo 1/2/3
• Durable elastomer designed to resist oil, fuel, and saltwater exposure
• Restores exhaust routing to prevent exhaust fumes and noise leaks

What fitment and compatibility should I check before ordering?

The 18654A1 bellows is intended for MerCruiser sterndrives labeled Alpha Gen 1, Alpha Gen 2, and Bravo 1–3. Verify your drive model and compare the old bellows’ external shape and bolt pattern to ensure the replacement matches.

• Fits Alpha Gen 1 & Gen 2 lower units
• Compatible with Bravo 1, Bravo 2, and Bravo 3 drives
• Confirm OEM part number 18654A1 or visual match with existing boot

What should I expect during installation and maintenance?

Installation typically requires removing the lower unit or swinging the drive aside to access the exhaust elbow and old bellows. Use appropriate clamps and torque specs, replace associated clamps or seals if corroded, and inspect adjacent hoses and muffler components while you have access.

• Basic tools needed: wrenches, clamps, marine-grade sealant if recommended
• Inspect and replace clamps, gaskets, or supporting hoses concurrently
• Regularly check bellows for cracking during seasonal maintenance

Why choose mariine aftermarket instead of a used or generic boot?

Aftermarket parts like this mariine item offer new-material elasticity and predictable lifespan compared with used or heat-aged bellows. The replacement is manufactured to meet original geometry so it seals and performs like the factory part at a fraction of dealership pricing.

• New elastomer avoids hidden cracks common with used boots
• Cost-effective alternative to OEM while maintaining fitment
• Backs easy do-it-yourself or professional replacement with consistent sizing

Who is this for: Boat owners, marine technicians, and restoration professionals who need a reliable, correctly sized replacement for MerCruiser Alpha Gen 1/2 and Bravo 1–3 exhaust bellows. Ideal for seasonal maintenance, refits, or troubleshooting exhaust leaks and vibration issues on sterndrive boats that use part 18654A1.