Keep coolant and gear lube exactly where they belong with the Yamaha O-Ring - 93210-94003-00. Cut to a true 94 mm inner diameter with a 3 mm cross-section, this nitrile seal slips between the lower-casing drive and water-pump housing on a wide range of four-stroke V-6 and offshore V-8 models, including the 4.2 L "bullet" gearcase. One simple ring, but it's the difference between a crisp-running pump and an overheated haul-out.. Compression-molded from fuel- and salt-resistant NBR rubber, the gasket stays pliable even after seasons of hot running, long lay-ups, and muddy ramp launches. Precision flash-trimmed edges hug the machined groove so you can torque the bolts once and walk away-no RTV mess, no second guesses.. Why this little ring matters. Exact OEM dimensions - 94 × 3 mm profile seats perfectly; no trimming or stretching.. Marine-grade NBR - shrugs off glycol, gear oil, and saltwater without cracking.. Re-service friendly - lifts clean on teardown, sparing the housing from razor