Sierra Voltage Regulator 18-99407, Replaces Johnson/Evinrude 584205, Fits 120-140 HP 4-Cylinder Outboards 1985-2001

The Sierra Voltage Regulator 18-99407 is a 10-amp voltage regulator built for 4-cylinder Johnson/Evinrude loop charged outboard engines. It manages charging system output from the engine's stator to the battery, protecting the electrical system from overcharging while keeping onboard batteries properly topped off during operation. This regulator is designed as a direct fit for 120, 125, 130, 135, and 140 HP loop charged outboards built between 1985 and 2001, and it cross-references to several original Johnson/Evinrude part numbers, making it a straightforward replacement when an original regulator has failed or is showing signs of erratic charging performance.

Voltage regulators are a common failure point on aging outboards, often showing up as a battery that will not hold a charge, a battery that overcharges and boils dry, or inconsistent gauge and accessory power. Replacing a worn unit with the 18-99407 restores predictable charging output without the cost of tracking down a used or discontinued OEM part. The regulator ships ready to install using the factory mounting and wiring configuration for the applicable engine.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99407
• Amperage Rating: 10 Amp
• Cylinder Configuration: 4 Cylinder
• Weight: 0.8 pounds
• Package Dimensions: 7.72 x 4.69 x 2.52 inches
• UPC: 808282394387

Fitment

• Johnson/Evinrude loop charged outboards, 120, 125, 130, 135, and 140 HP (1985-2001)

Replaces (OEM)

• 584205
• 583512
• 582907
• 584675
• 585192
• 878332

Frequently Asked Questions

What engines does the Sierra 18-99407 voltage regulator fit? The Sierra 18-99407 fits Johnson/Evinrude loop charged outboards rated 120, 125, 130, 135, and 140 HP built from 1985 to 2001.

Is this a 4-cylinder or 6-cylinder voltage regulator? The 18-99407 is built for 4-cylinder Johnson/Evinrude loop charged outboard engines.

What amperage is the 18-99407 rated for? This regulator is rated at 10 amps, matching the output of the Johnson/Evinrude charging systems it replaces.

Which original Johnson/Evinrude part numbers does 18-99407 replace? It replaces OEM numbers 584205, 583512, 582907, 584675, 585192, and 878332.

How much does the 18-99407 voltage regulator weigh? The regulator weighs 0.8 pounds.

What are the package dimensions of the 18-99407? It ships in a package measuring 7.72 x 4.69 x 2.52 inches.

Will this regulator work with a 6-cylinder Johnson/Evinrude outboard? No, the 18-99407 is designed for 4-cylinder loop charged Johnson/Evinrude outboards in the 120-140 HP range, not 6-cylinder models.

How do I know if my outboard's voltage regulator has failed? Common symptoms include a battery that will not hold a charge, a battery that overcharges or boils dry, or inconsistent electrical accessory performance; the 18-99407 addresses these issues on applicable Johnson/Evinrude engines.

Does the 18-99407 use the factory wiring and mounting? Yes, it is designed to install using the factory mounting and wiring configuration for the applicable Johnson/Evinrude engine.

Is the Sierra 18-99407 a new part or remanufactured? The 18-99407 is supplied as a new replacement voltage regulator, not a remanufactured or used unit.

What year range of outboards does this regulator cover? Coverage is for Johnson/Evinrude 120-140 HP loop charged outboards built in the 1985 to 2001 range.

Can I cross-reference this part using an old Johnson/Evinrude regulator number? Yes, if your old regulator is stamped 584205, 583512, 582907, 584675, 585192, or 878332, the Sierra 18-99407 is the corresponding replacement.