Voltage Regulator Rectifier for Mercury 75-90 HP 4 Stroke 804278A12

Product Overview

This voltage regulator rectifier converts AC voltage from the stator to regulated DC voltage for charging the battery and powering electrical systems on Mercury 75–90 HP 4-stroke outboards. It maintains stable output to protect sensitive electronics and ensure reliable engine operation. Designed for direct OEM replacement, it restores proper charging performance on compatible Mercury marine engines.

Key Features & Performance

• Direct replacement for OEM part numbers 804278A12 and 804278T11
• Regulates output to maintain stable battery charging voltage
• Solid-state design for long service life in marine environments
• Plug-and-play installation with factory-style connectors
• Compatible with Mercury 75, 80, 85, and 90 HP 4-stroke outboards

Fitment & Compatibility

• Compatible with Mercury Marine 75 HP 4-stroke outboard engines
• Compatible with Mercury Marine 80 HP 4-stroke outboard engines
• Compatible with Mercury Marine 85 HP 4-stroke outboard engines
• Compatible with Mercury Marine 90 HP 4-stroke outboard engines
• Replaces OEM part numbers 804278A12 and 804278T11

Common Uses

• Replacement of failed or underperforming voltage regulators on Mercury 4-stroke outboards
• Restoring charging system function on fishing, cruising, and utility boats
• Maintenance and repair of Mercury outboard electrical systems

Technical Specifications

• Part Number(s): 804278A12, 804278T11
• Type: Voltage Regulator Rectifier
• Polarity: Negative ground
• Connector: Weatherpack-style connector (integrated)

Frequently Asked Questions

Q: Will this voltage regulator rectifier work on my Mercury 90 HP 4-stroke from 2005? A: Yes, it is designed for Mercury 75–90 HP 4-stroke outboards, including 2005 model years, as a direct replacement for 804278A12 and 804278T11.

Q: Does it come with mounting hardware or just the unit? A: The unit includes the regulator/rectifier only; mounting screws and wiring are sold separately if needed.

Product appearance and specifications may vary slightly by batch. Compatibility may vary by serial number. Verify fitment before purchase.