Yamaha Spring Retainer - 6S5-R2358-00-00. Tiny but tough, this steel "top hat" lives on the business end of every 1.8-liter Yamaha marine engine, locking each valve spring in perfect alignment so your SVHO or HO powerplant can spin cleanly past 7,000 rpm. Yamaha machines the retainer from heat-treated chromoly, then gives it a dark phosphate finish that shrugs off heat, oil acids, and the occasional salt-spray mist that sneaks past the cover.. Why it earns a place in your rebuild kit:. OEM geometry mates precisely with factory keepers-no lapping, no guesswork.. Lightweight profile keeps valve-train mass low, protecting cam lobes at sustained wide-open throttle.. Phosphate coating resists corrosion far longer than bright-metal aftermarket copies.. Direct fit for late-model 1.8 L jet-boat and WaveRunner engines-GP, FX, and F-series outboards that share the block.. Swapping a worn or pitted retainer during your winter teardown means rock-solid spring tension, cleaner idle, and crisper thr