Having a heavy-duty alternator for your boat is very important. If your battery often fails, overheats, and has a bad smell from the alternator, it might be a serious indicator that there is something to be fixed to prevent damages to your boat soon. There s no need to be worried! Alternator - ARCO Marine (60125) is available for you. This Arco Alternator - ARCO Marine (20800) is a high-performance alternator designed for reliability and performance. It has an internal regulator and a negative ground, which ensures that this alternator performs optimally. The Arco Alternator - ARCO Marine (20800) has a 55 amp 12-volt marine alternator with 2 inches mounting foot and a single v-groove pulley that is manufactured with precision and quality. Key Features: A 55 amp 12-volt marine alternator 2 inches mounting foot single v-groove pulley It has an internal regulator It has negative ground Replaces Volvo Penta 3860769 Replaces OMC 988247, 985465, 985466, 3857298, and 3860769 Specifications: Brand: Arco Marine SKU: 20800 UPC: 693006008172 Weight: 8.00 LBS Manufacturer Part Number (MPN): 20800 12 volt. 70 amp. Internal fan. 65mm multigroove serpentine pulley included. Fits: Mercruiser 4.3L-8.2L 1998-up