This exhaust sleeve for MerCruiser is the Stern Drive variant for the exhaust connection at the drive's bell housing/transom assembly. It corresponds to Mercury/MerCruiser OEM reference 78458A1 and is used as a short, flexible connection in the exhaust system.
The sleeve is made of black rubber and features a non-corrugated construction. It routes exhaust through the connection at the sterndrive, differing from a full bellows-style exhaust tube. The product height is 123 mm. The diameter pair at the upper end is Ø 73 × 56 mm, while the lower end is Ø 91 × 67 mm.
OEM reference 78458A1 is documented for a range of MerCruiser installations, including 120/140, 165, 228, 260, 470, 485, and 898, as well as R/MR/Alpha One drives and transom assemblies from relevant years and serial number ranges. It also appears in documented applications for, among others, Blackhawk and selected Bravo installations. Specific compatibility must be determined based on the OEM number, drive model, and serial number.
Replaces OEM numbers
Primary Mercury/MerCruiser reference: 78458A1.
Previous OEM number: 78458.
Documented cross-references: CEF 500520K, Sierra 18-2760, Mallory Marine 9-72810, and GLM 89150.
Related service kits
Mercury/MerCruiser 30-803098T1 and GLM 21951 are documented transom service kits related to this type of exhaust tube. A complete service kit is not necessarily required for every replacement.
Always check the engine/drive model, serial number, and original part number before purchasing.
Key featuresExhaust sleeve for MerCruiser Stern Drive
For bell housing/transom assembly
Corresponds to OEM reference 78458A1
Height: 123 mm
Upper end: Ø 73 × 56 mm
Lower end: Ø 91 × 67 mm
Flexible, non-corrugated rubber construction
Color: Black
