Sierra Voltage Regulator 18-5741, Replaces 815279A2 and 815279-1, for Mercury 16/40 Amp Charging Systems 1989-91

The Sierra 18-5741 Voltage Regulator is a direct-fit replacement regulator for Mercury outboard engines equipped with a 16 amp or 40 amp charging system, model years 1989-91. The voltage regulator manages the output of the engine's charging system, protecting the battery and onboard electronics from overcharging while ensuring consistent electrical performance on the water.

This regulator is built to match the original Mercury part it replaces, so it installs using the existing wiring and mounting points on applicable 1989-91 Mercury engines with 16 amp or 40 amp charging systems. It is a compact, mount-ready component intended as a straightforward swap for a failed or aging factory voltage regulator.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5741
• UPC: 808282239992
• Category: Mercury Outboard Voltage Regulator
• Weight: 0.86 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• OEM Cross-Reference: 815279A2, 815279-1

Fitment

• Mercury engines with 16 amp or 40 amp charging system, model/years 1989-91

Replaces (OEM)

• 815279A2
• 815279-1

Frequently Asked Questions

What does the Sierra 18-5741 voltage regulator fit? The Sierra 18-5741 fits Mercury engines equipped with a 16 amp or 40 amp charging system, model/years 1989-91.

What OEM part numbers does the 18-5741 replace? It replaces Mercury 815279A2 and 815279-1.

How much does the 18-5741 voltage regulator weigh? It weighs 0.86 pounds.

What are the dimensions of the 18-5741? The regulator measures 0.39 x 0.39 x 0.39 inches.

Is the Sierra 18-5741 a direct OEM replacement? Yes, the 18-5741 is designed to install as a direct replacement for Mercury 815279A2 and 815279-1 regulators on applicable 1989-91 engines.

Will this regulator work on a 16 amp charging system as well as a 40 amp system? Yes, the 18-5741 is designed for Mercury engines with either a 16 amp or 40 amp charging system, model/years 1989-91.

Does the 18-5741 include mounting hardware? The Sierra 18-5741 is the voltage regulator unit itself; the dossier does not list included mounting hardware.

What is the UPC for the Sierra 18-5741 voltage regulator? The UPC for the Sierra 18-5741 is 808282239992.

Can I use the 18-5741 on a Mercury engine outside the 1989-91 range? The 18-5741 is specified for Mercury engines with 16 amp or 40 amp charging systems in model/years 1989-91; fitment outside that range is not confirmed.

Why would I need to replace a voltage regulator like the 18-5741? A voltage regulator controls charging output to the battery and electrical system; a failing unit can cause overcharging or a battery that won't hold a charge, and the 18-5741 is built to restore that function on applicable 1989-91 Mercury engines.