Sierra 18-5821 Starter Solenoid, Replaces Yamaha 6G1-81941-10-00, Fits Yamaha Outboards 9.9-F100 HP

The Sierra 18-5821 is a 12-volt starter solenoid built as a direct replacement for the Yamaha outboard electrical system, cross-referencing OEM number 6G1-81941-10-00. It handles the high-current switching load between the ignition key circuit and the starter motor, delivering the power surge needed to crank the engine on demand. The solenoid is rated at 10 amps with a 1.4 kilowatt switching capacity, giving it the current-handling headroom required for reliable starts across a wide range of Yamaha outboard horsepower classes.

Housed in a compact white enclosure measuring 3.56 x 2.19 x 2.5 inches, the 18-5821 is sized to mount in the factory location without modification. It covers Yamaha outboards spanning small tiller engines like the 9.9/15 hp up through larger four-stroke F-series models including the F90 and F100. Because it is built to the same electrical specification as the original equipment part, it engages and disengages the starter circuit with the same responsiveness as the OEM solenoid it replaces. Sierra backs the part with a limited warranty.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5821
• Product Type: Starter Solenoid
• Voltage: 12 Volts (DC)
• Amperage: 10 Amps
• Wattage: 1.4 KW
• Color: White
• Item Dimensions: 3.56 x 2.19 x 2.5 inches
• Weight: 0.29 pounds
• Unit Count: 1
• OEM Cross-Reference: 6G1-81941-10-00

Fitment

• Yamaha Outboard 9.9/15 hp (1988-1997)
• Yamaha Outboard 20 hp (1996-1997)
• Yamaha Outboard 25 hp (1985, 1988-1999)
• Yamaha Outboard 30 hp (1985-1987, 1989-1993, 1996-1999, 2001)
• Yamaha Outboard 40 hp (1989-1990, 1992-2001)
• Yamaha Outboard 50 hp (1989-1997, 1999-2002)
• Yamaha Outboard 90 hp (1992-2002)
• Yamaha Outboard F15 (1998-2003)
• Yamaha Outboard F40 (1999)
• Yamaha Outboard F50 (1996-2002)
• Yamaha Outboard F60 (2002-2003)
• Yamaha Outboard F75 (2003-2004)
• Yamaha Outboard F80 (1999-2003)
• Yamaha Outboard F90 (2003-2004)
• Yamaha Outboard F100 (1999-2002)

Replaces (OEM)

• 6G1-81941-10-00

Frequently Asked Questions

What does the Sierra 18-5821 starter solenoid replace? It replaces Yamaha outboard OEM part number 6G1-81941-10-00, using the same 12-volt, 10-amp electrical specification.

Is the 18-5821 solenoid 12 volt? Yes, the Sierra 18-5821 operates on a 12-volt DC electrical system with a 10-amp rating and 1.4 kilowatt switching capacity.

Which Yamaha outboards fit the 18-5821 starter solenoid? Coverage spans Yamaha outboards from 9.9/15 hp and 20 hp through larger models including 30, 40, 50, and 90 hp, plus F-series four-strokes F15, F40, F50, F60, F75, F80, F90, and F100, with specific model years varying by horsepower.

Will this solenoid fit a Yamaha F100? Yes, the 18-5821 is listed for the Yamaha F100 outboard for the 1999-2002 model years.

Does the 18-5821 fit the Yamaha F90? Yes, it fits the Yamaha F90 outboard for the 2003-2004 model years.

What are the dimensions of the Sierra 18-5821? The solenoid measures 3.56 x 2.19 x 2.5 inches.

How much does the 18-5821 starter solenoid weigh? It weighs 0.29 pounds.

What color is the Sierra 18-5821 solenoid? The housing is white.

Is the Sierra 18-5821 an OEM or aftermarket part? The 18-5821 is a Sierra aftermarket solenoid built to match the electrical specification of Yamaha OEM part 6G1-81941-10-00.

How many solenoids come in the package? The 18-5821 ships as a single starter solenoid unit.

What is the amperage rating of this starter solenoid? The Sierra 18-5821 is rated at 10 amps.

Is the Sierra 18-5821 covered by a warranty? Yes, it is backed by Sierra's limited warranty.