R & D Engine Mount w/6.85" Footprint - 5/8" Stud - 120-410lbs Capacity Per Mount (Yanmar***)

The R & D Engine Mount with 6.85" Footprint and 5/8" stud is a heavy-duty marine engine isolation system designed specifically as a rear mount for Yanmar 4JH series engines. Built to handle up to 120–410 lbs capacity per mount, this engine mount delivers the precise balance marine operators need: rigid enough to absorb forward and reverse propeller thrust, yet compliant enough to isolate drivetrain vibration from the hull and cabin.

All steel components are zinc-plated and passivated to resist corrosion in salt spray and freshwater environments—a critical feature for extended offshore and coastal operation. The 5/8" stud diameter and 6.85" footprint match OEM Yanmar specifications, ensuring direct bolt-down compatibility without adapter plates or drilling modifications. Proper engine mounting is fundamental to long-term reliability; inadequate isolation transfers vibration to through-hull fittings, accelerates fatigue in the hull structure, and transmits noise into living spaces. This mount's engineering addresses all three concerns.

Yanmar 4JH operators—whether running commercial fishing platforms, offshore cruising sailboats, or work vessels—depend on engine mounts that perform under continuous throttle cycles and rough water. This rear-mount configuration works in concert with forward mounts to manage thrust loads while maintaining the engine's lateral stability. Replacement or upgrade of worn mounts restores vibration isolation and reduces stress on engine beds, transmission coupling, and exhaust manifolds. At 4.05 lbs per unit, the compact design fits tight engine compartments without sacrificing load capacity.