Hynautic R-04 Hydraulic Engine Control System Reservoir With Gauge - Used

Hynautic R-04 pressurized reservoir for Hynautic hydraulic ENGINE CONTROL (throttle/shift) systems — the style widely used on inboard diesel yachts and sportfish boats with Hynautic controls (now supported by SeaStar Solutions). Complete as shown with aluminum canister, external sight tube, top and bottom fittings, 0–150 PSI pressure gauge, air charging valve, and original mounting bracket/board. Factory label is legible and shows Model No. R-04, 1 gallon capacity, 90 PSI max working pressure, and the original fill/purge instructions. Condition: used take-off, untested. Appears complete with surface oxidation on the aluminum and light corrosion/staining on the mounting board and hardware. Not pressure or leak tested; seals and sight tube should be inspected or replaced before service. Reservoir will be drained and ports capped before shipping. Buyer must confirm fitment by part number, photos, dimensions, engine model, serial number, and application before purchase. Used marine part sold as-is unless otherwise stated. No returns on electrical, used, special-order, or installed parts.