Introduction
This manual provides essential information for the proper installation, operation, and maintenance of your Sierra 18-5744 Marine Voltage Regulator. Please read these instructions thoroughly before proceeding with installation or use to ensure safe and optimal performance.
Product Overview
The Sierra 18-5744 is a high-quality marine voltage regulator designed to maintain a stable voltage output from your outboard motor's charging system. This ensures proper charging of the battery and protects the electrical system from overvoltage conditions. It is engineered to meet or exceed original equipment specifications for reliability and durability in marine environments.

Image: The Sierra 18-5744 Marine Voltage Regulator, showing its compact design and attached wiring harness with various colored wires (grey, yellow, red).
Compatibility
This voltage regulator is specifically designed for use with:
- Force engines equipped with a 16 Amp to 20 Amp charging system.
- Applicable to model years 1993 to present.
It is interchangeable with the following OEM part numbers:
- Chrysler/Force/US Marine: 815279-4, 815279T4, 815279T5, 8174111, 830179A1, 854514A1, 856747T1, 883071A1.
Always verify compatibility with your specific engine model before installation.
Safety Information
Working with marine electrical systems requires caution. Adhere to the following safety guidelines:
- Disconnect Battery: Always disconnect the battery's negative terminal before performing any electrical work on your outboard motor.
- Wear Protective Gear: Use appropriate personal protective equipment, including safety glasses and gloves.
- Avoid Water Contact: Ensure the work area is dry and avoid contact with water during installation.
- Professional Installation: If you are unsure about any step, consult a qualified marine technician.
- Check Wiring: Ensure all connections are clean, secure, and free from corrosion.
Installation Instructions
The following steps provide a general guide for installing the Sierra 18-5744 Voltage Regulator. Specific procedures may vary based on your engine model. Refer to your engine's service manual for detailed instructions.
- Prepare: Ensure the engine is off and the battery's negative terminal is disconnected. Gather necessary tools (e.g., wrenches, screwdrivers, wire crimpers).
- Locate Old Regulator: Identify the existing voltage regulator on your outboard motor. It is typically mounted near the alternator or flywheel.
- Disconnect Old Regulator: Carefully disconnect all wiring from the old regulator. Note the position and color of each wire for correct re-connection. Remove any mounting hardware.
- Mount New Regulator: Position the Sierra 18-5744 in the same location as the old regulator. Secure it using appropriate mounting hardware. Ensure a good ground connection if applicable.
- Connect Wiring: Connect the wires from the engine harness to the new voltage regulator. Match the wire colors and terminals precisely as noted during removal. Ensure all connections are tight and secure.
- Reconnect Battery: Once all connections are verified, reconnect the battery's negative terminal.
- Test System: Start the engine and check the charging system's voltage output using a multimeter. The voltage should be stable and within the manufacturer's specified range (typically around 13.8-14.5 volts DC at moderate RPMs).
If the charging system does not operate correctly after installation, refer to the Troubleshooting section.
Operation
The Sierra 18-5744 Voltage Regulator operates automatically to regulate the electrical output from your outboard motor's charging system. Its primary function is to convert the alternating current (AC) generated by the stator into direct current (DC) and maintain a consistent voltage level for charging the battery and powering the boat's electrical accessories. Once installed correctly, no user intervention is required for its operation.
Maintenance
The Sierra 18-5744 Voltage Regulator is designed for minimal maintenance. However, periodic inspection can help ensure its longevity and proper function:
- Visual Inspection: Annually inspect the regulator and its wiring for any signs of corrosion, fraying, or damage.
- Connection Integrity: Ensure all electrical connections remain tight and free from oxidation. Clean any corroded terminals.
- Mounting Security: Verify that the regulator is securely mounted and not vibrating excessively.
Troubleshooting
If you experience issues with your charging system after installing the Sierra 18-5744 Voltage Regulator, consider the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Battery not charging / Low voltage |
|
|
| Battery overcharging / High voltage |
|
|
| Intermittent charging |
|
|
For further assistance, contact Sierra customer support or a certified marine technician.
Specifications
- Brand: Sierra
- Model: 18-5744
- Part Number: 18-5744 (Manufacturer Part Number: 185744)
- Voltage: 12 Volts (DC)
- Engine Type Compatibility: 2 Stroke or 4 Stroke (for Force engines with 16-20 Amp charging system)
- Item Weight: 9.6 ounces
- Product Dimensions: 4.5 x 2.63 x 2.63 inches
- OEM Part Number Cross-reference: CHRYSLER FORCE 815279-4
- UPC: 808282244477
Warranty and Support
All Sierra parts are covered under Sierra's industry-leading customer satisfaction warranty. For specific warranty details, claims, or technical support, please refer to the official Sierra website or contact their customer service department. You can also visit fit-guide.seastarsolutions.com to ensure product fitment for your application.





