Yanmar 728170-53100 Relief Valve Assembly - New Old Stock

New old stock Yanmar relief valve assembly, OEM part number 728170-53100, in original Japanese OEM box. Cartridge-style screw-in relief/bypass valve with hex adjustment head, O-ring sealed seat, and small metering orifice — typically used in lube oil or low-pressure circuits on Yanmar E-series and related applications. Unused part; box shows age and label staining, valve itself is clean with no corrosion. Application: Yanmar (E-series reference on box tag) — verify against your engine's parts catalog. Condition: New (old stock). Buyer must confirm fitment by part number, photos, dimensions, engine model, serial number, and application before purchase.