Sierra 18-99421 MerCruiser Voltage Regulator 40 Amp Water Cooled

The Sierra 18-99421 is a water-cooled voltage regulator designed specifically for MerCruiser stern drive engines. This replacement voltage regulator ensures stable charging system performance by regulating the rate at which your battery charges, preventing electrical surges that can damage sensitive marine electronics and other electrical components.

Key Features:

• Water-cooled design for reliable performance in marine environments
• 40 amp charging system capacity
• Direct replacement for MerCruiser part number 99502A13
• Compatible with CDI Electronics part number 194-9502
• Meets or exceeds OEM specifications

Fits MerCruiser Models:

• 1976-1984: 470 series (2 BBL Carb)
• 1980-1984: 485 and 488 series (2 BBL Carb)
• 1985-1986: 170 and 190 series
• 1987: 165 and 180 series
• 1988-1989: 3.7L (224 CID) 4-cylinder water-cooled engines

Cross Reference Numbers:

• MerCruiser: 99502A13, 99502A12, 99502A9, 99502A8, 99502A7, 99502A4, 86255A3, 86255A2, 77305A2
• CDI Electronics: 194-9502

This voltage regulator is an essential component of your MerCruiser stern drive's charging system, helping to extend battery life and protect your engine's electrical components from voltage fluctuations and overcharging.