ALTERNATOR FITS 73-78 MERCRUISER STERN DRIVE 225 228 233 1100576 1100577 1100619 1100654 1100721 1100722 20102 100% NEW and Made with the Highest Quality Components Available Full One Year Warranty Computer tested for consistent Quality and unsurpassed reliability Alternator - Voltage: 12V Amperage: 110 Amps Fan: External Regulator: Internal Pulley: V Belt Grooves: 1 Source: Aftermarket