The Vibration-Damping Mount Kit from Buckshot Racing #77 is engineered as a direct replacement for Mercury Marine and Mercury Racing OEM part numbers 12234 and 90435.
These mounts were widely installed across Mercury’s 2.0L, 2.4L, and 2.5L 2-stroke outboard platforms, including high-performance models such as the 260 EFI, 2.5 ROS, S3000, and Champ, as well as production outboards including the XR2, XR4, XRi, Bridgeport, 175 HP, 200 HP, and 225 Pro Max.
Some earlier clamshell cowl outboards from 1976 through 1988 also relied on these mounts for cowling isolation off the exhaust divider plate.
Functional Role of the Mercury 12234 and 90435
The Mercury 12234 mount was primarily used for electronic control unit (ECU) and EFI Fuel Pressure Regulator vibration isolation and for stabilizing EFI fuel pressure regulators. The 90435 mount, by contrast, was most often integrated into cowling and ECU support assemblies.
In both cases, the function was the same: to provide a compliant interface between structural brackets and sensitive components, reducing harmonic transfer from the crankcase and intake assembly into electronic housings.
When these mounts fail, vibration is transmitted directly into wiring harnesses, regulators, and ECU enclosures. This leads to accelerated fatigue, structural wear, and in many cases, premature component failure. With years of service, the original OEM rubber elements tend to harden, crack, or lose elasticity, leaving them unable to perform their damping role effectively.
Technical Construction of the Buckshot Racing #77 Mount
The Buckshot Racing #77 mount maintains the original Mercury dimensional envelope while updating the material properties to improve consistency and durability.
Each mount is manufactured from natural rubber bonded to zinc-plated steel studs, a combination chosen to balance vibration absorption with corrosion resistance. The design supports a static capacity of 50 pounds per mount with an additional shear rating of 9 pounds.
The rubber compound is formulated to a Durometer 50A hardness rating, providing medium compliance suitable for absorbing engine harmonics while maintaining the structural integrity required in high-performance marine environments.
The operating temperature range extends from –10°F to 150°F, ensuring stability in both cold-weather starting conditions and high-heat engine compartments.
All Buckshot Racing #77 mounts are produced in the United States. They are compliant with DFARS specialty metals exemptions, conform to REACH regulations (EC 1907/2006), and meet RoHS 3 standards (2015/863/EU) for environmental and material safety requirements.
Installation and Compatibility
Installation follows the same procedure as with Mercury OEM 12234 and 90435 mounts. The component fits directly between the bracket and housing interfaces, utilizing the existing fasteners.
No modifications are required, as the mount is dimensionally interchangeable with the factory parts. Common applications include ECU vibration isolation brackets, EFI fuel pressure regulator mounts, and cowling support systems used across Mercury 2-stroke performance platforms.
The Buckshot Racing #77 vibration-damping mount provides a precise technical replacement for Mercury OEM 12234 and 90435. Its material composition, dimensional properties, and compliance certifications equal or exceed those of the original Mercury parts.
For use in ECU, regulator, and cowling assemblies on Mercury’s 2.0L, 2.4L, and 2.5L 2-stroke outboards, the #77 mount restores effective vibration isolation while meeting modern standards of performance and reliability.
Each kit includes: one (1) Vibration-Damping Mount, two (2) Stainless Washers, one (1) Stainless Nylock Nut, and one (1) Stainless THIN Nylock Nut.
For technical support, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com