804278A12 804278T11 Regulator Rectifier for Mercury Yamaha F75 F80 F90 F100 | JLM Marine

Regulator Rectifier for Mercury Yamaha F75 F80 F90 F100 Outboard Motors

This aftermarket Voltage Regulator Rectifier is designed as a direct replacement for Mercury 75-90 HP 4-Stroke outboards (2000-2005) and Yamaha F75, F80, F90, and F100 4-Stroke models (1999-2004). Engineered to match OEM specifications, it ensures reliable voltage regulation and charging performance across a broad range of mid-power outboard applications.

This unit directly replaces Mercury OEM part numbers 804278A12, 804278T11, 804278T12, and 804278T, as well as Yamaha part numbers 67F-81960-10, 67F-81960-11, 67F-81960-12, and 67F-81960-00.

• Plug-and-play design with no assembly required—direct fit for quick installation
• Features improved heat sink design and higher-grade electrical components for enhanced durability
• Each unit is factory-tested before shipping to ensure reliable performance

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

For Yamaha owners, here's a guide to help you identify your engine's serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 × Voltage Regulator Rectifier

Note: The package contains all the parts shown in the picture.

Installation Guide

1. Disconnect the battery and ensure the ignition is off before beginning installation.
2. Locate the existing regulator rectifier on your outboard motor, typically mounted near the engine's electrical system.
3. Disconnect all wiring harness connectors from the old regulator rectifier. Take note of the connector positions or take a photo for reference.
4. Remove the mounting bolts securing the old unit to the engine bracket.
5. Position the new regulator rectifier in the same location and align the mounting holes.
6. Secure the new unit with the original mounting bolts, ensuring a snug fit without over-tightening.
7. Connect each wiring harness plug to the corresponding socket on the new regulator rectifier. The connectors are keyed to prevent incorrect installation.
8. Double-check all electrical connections to ensure they are fully seated and secure.
9. Reconnect the battery, ensuring correct polarity (positive to positive, negative to negative).
10. Start the engine and verify that the charging system is functioning properly by checking the battery voltage with a multimeter (should read approximately 13.5–14.5 volts at idle).
11. Inspect the regulator rectifier for excessive heat after a short test run; it should warm but not become excessively hot.
12. If any issues arise, immediately shut down the engine and recheck all connections and mounting points.

Troubleshooting & FAQ

Q: How do I confirm this regulator rectifier fits my specific engine?
A: Cross-reference your engine's model, year, and OEM part number with our compatibility table above. You can also check your engine's serial number using the guides provided or consult your engine's parts diagram to verify the exact part number currently installed.

Q: What are the signs that my regulator rectifier is failing?
A: Common symptoms include a dead or undercharged battery, dimming lights at idle, erratic electrical system behavior, or the battery overheating. If you measure voltage output above 15 volts or below 13 volts while the engine is running, the regulator rectifier may be faulty.

Q: How often should I replace the regulator rectifier?
A: Regulator rectifiers typically last several years under normal operating conditions. Replace it if you experience charging system issues, visible corrosion, or heat damage. Regular electrical system inspections during annual maintenance can help catch problems early.

Q: What's the difference between this aftermarket part and the OEM version?
A: This aftermarket unit is built to match OEM specifications and dimensions. It features higher-grade electrical components and an improved heat sink design for enhanced durability and charging performance, often at a more competitive price point than OEM parts.

Q: Can I install this myself, or do I need a professional?
A: Installation is straightforward for those with basic mechanical skills and familiarity with outboard electrical systems. The plug-and-play design simplifies the process. However, if you're uncomfortable working with electrical systems, we recommend professional installation to ensure safety and optimal performance.

Q: Is this an OEM part or an aftermarket replacement?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.