UANOFCN Exhaust Bellows Tube for MerCruiser Alpha One Gen II & Bravo — Direct-Fit, Reinforced Replacement (78458A1)

UANOFCN 78458A1 Exhaust Bellows Tube is a direct-fit replacement bellows designed to restore proper exhaust routing for MerCruiser Alpha One Gen II, Bravo and compatible stern drive models.

When an exhaust bellows cracks or collapses it can allow water into the drive, cause vibration, and compromise performance. This UANOFCN bellows tube replaces Mercury part numbers 78458A1, 78458 and GLM 89150, and is built for MerCruiser R, MR, Alpha One (including Gen II) and Bravo sterndrives within the specified serial ranges. The piece arrives brand new and is engineered to withstand marine conditions while providing a precise fit for straightforward installation.

Will this bellows fit my MerCruiser Alpha One Gen II or Bravo sterndrive?

Check your drive's serial number and model to confirm compatibility. This bellows covers MerCruiser R, MR, Alpha One serial numbers 6225577 and up (1983–1990), Bravo I/II/III serial numbers OB664190 and up (1988 and later), and Blackhawk drives with serial 0F18677 and up (1994–1995).

• Direct replacements for Mercury part# 78458A1, 78458 and GLM 89150.
• Fits specified R, MR, Alpha One Gen II and Bravo drive serial ranges.
• Designed for MerCruiser Alpha & Bravo sterndrive engines.

How durable is the UANOFCN exhaust bellows under marine conditions?

The bellows is manufactured to endure exposure to saltwater, vibration and engine movement typical of sterndrive operation. UANOFCN collaborated with local workshops to validate materials and construction, aiming for long service life under tough conditions.

• Reinforced flexible bellows material resists cracking and collapse.
• Precision molding minimizes leaks and improves sealing.
• Quality checks performed in partnership with experienced marine technicians.

What should I expect during installation and maintenance?

Installation is straightforward for anyone familiar with sterndrive disassembly; the unit is a direct-fit replacement so no custom trimming is normally required. Routine visual inspections and replacement at the first sign of wear will protect the drive from water intrusion and mechanical damage.

• Direct-fit design reduces install time compared with generic bellows.
• Inspect clamps and surrounding seals when replacing the bellows.
• Replace bellows at first evidence of tears, cracking or deformation.

What exact models and serial ranges does this part replace?

This UANOFCN bellows replaces factory and aftermarket part numbers for multiple MerCruiser drives across specific production years. Always match your drive’s serial number before purchasing to ensure a correct fit.

• MerCruiser R / MR / Alpha One serial no. 6225577 & up (1983–1990).
• Bravo I, II, III serial no. OB664190 & up (1988 and later).
• Blackhawk serial no. 0F18677 & up (1994–1995).

Who is this for: Boat owners, marine technicians and DIY mechanics who operate MerCruiser Alpha One Gen II, Bravo or compatible sterndrives needing a reliable, OEM-equivalent exhaust bellows replacement. If you want to prevent water ingress, reduce vibration and restore correct exhaust flow with a new, engineered part that matches Mercury/MerCruiser part numbers, this UANOFCN 78458A1 unit is aimed at that repair or maintenance job.