12V 50A Alternator, Internal Fan, Negative Polarity, Clockwise Rotation Description A directreplacement 12 volt alternator delivering 50 amps of charging capacity. Designed for applications that require a compact, clockwiserotation alternator with an internal cooling fan and single groove pulley. Suited for marine and small engine installations where negative polarity charging systems are used. Key benefits Restores reliable battery charging: 50 amp output meets the needs of common 12 volt electrical systems and onboard accessories. Compact and serviceable: internal fan reduces exposure to external debris while maintaining cooling performance. Easy to fit: designed mounting ears and standard threaded stud allow straightforward installation into compatible mounts. Broad compatibility: listed part numbers provide a direct replacement option for a wide range of equipment and legacy units. Main specifications Function: alternator for 12 volt charging systems Voltage: 12 V Amperage: 50 A Polarity: negative Rotation: clockwise Fan: internal Grooves: 1 (single groove pulley) Weight: 8.9 lbs / 4.05 kg; 10 lbs Mounting ears: 2 Mounting ear 1: M81.25 threaded Mounting ear 2: unthreaded, 10.5 mm diameter, thickness 21 mm Compatibility and reference numbers Part numbers: 31A6800401, 686696121559, A7T02071, A7T02077, 32A6800302, 32A6800300, 32A6800302, STM7945, 32A6800301, A7T02077A, 31A6800402, A7T02071A, A7T02077C, 32A6800301, 31A6800402, 17227010, 31A6800401, 32A6800300, A7T02071C What makes this unit stand out Directfit mounting details reduce modification time and simplify installation. Internal fan provides protected cooling for longer service life in dirty or confined environments. Single groove pulley and clockwise rotation align with many small engine and marine drive configurations. Multiple equivalent part numbers make it easy to confirm compatibility with existing equipment. Typical applications Replacement alternator for small inboard marine engines where a 12 volt 50 amp negative polarity alternator with clockwise rotation is required. Service or spare unit for boats and watercraft that list any of the included part numbers as compatible replacements. Swapin replacement for gensets, industrial engines, or other equipment that use a single groove pulley and specified mounting ear configuration. Installation notes Confirm rotation direction and pulley groove count before installation. Verify mounting ear dimensions and threaded stud size against the receiving bracket to ensure a secure fit. Check electrical connections for negative system polarity and ensure proper battery and ground connections when installing. This alternator is supplied as a functional replacement unit matching the listed part numbers and technical specifications. Use the reference numbers above to confirm fitment for your equipment.