Sierra 118-6840 Marine Alternator 50A 12V for Mercury 75-115HP EFI 4-Stroke Outboards

The Sierra 118-6840 (18-6840) is a replacement marine alternator engineered for Mercury 75–115 HP EFI 4-Stroke outboard engines. Designed to meet or exceed OEM specifications, this 50-amp, 12-volt alternator delivers reliable charging performance and is a direct replacement for Mercury OEM part numbers 50-897755T and 8M0063970.

Key Features:

• 50 Amp / 12V output with internal voltage regulator
• Serpentine belt drive with corrosion-resistant plated pulley and hardware
• Marine-grade flame arrestor screens eliminate open sparks, reducing fire and explosion risk
• Meets or exceeds USCG and SAE J1171 marine safety requirements
• 100% load-tested for assured reliability before leaving the factory
• Wiring harness included for straightforward installation
• Replaces Mercury OEM part numbers: 50-897755T, 897755T, 8M0063970
• Alternate part number: 18-6840

Sierra International is a trusted name in marine replacement parts, producing components that match or surpass the performance of original equipment. The 118-6840 alternator is built with corrosion-resistant materials suited to the demanding marine environment, keeping your onboard electrical systems and battery properly charged on the water.