Sierra 18-6408 Marine Alternator - 105 Amp for Mercruiser Applications

The Sierra 18-6408 is a 105 amp marine alternator built for Mercruiser applications. It replaces a worn or failed alternator to restore reliable charging output for the battery and onboard electrical systems, keeping ignition, electronics, and accessories powered while underway. The housing features a machined exterior finish, and the unit measures 8 x 8 x 7 inches and weighs 9.3 pounds.

As a Sierra branded part, the 18-6408 is manufactured to work as a direct fit within Mercruiser electrical systems, making it a straightforward swap for boat owners and marine technicians performing a charging system repair or upgrade. Its 105 amp output supports demanding onboard electrical loads, making it a solid choice for boats that run additional electronics, lighting, or accessories alongside standard engine and helm systems.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-6408
• Product Name: Alternator
• Amperage: 105 Amp
• Exterior Finish: Machined
• Weight: 9.3 pounds
• Product Dimensions: 8 x 8 x 7 inches
• UPC: 808282378905

Fitment

Designed for Mercruiser alternator applications.

Frequently Asked Questions

What amperage does the Sierra 18-6408 alternator produce? The Sierra 18-6408 is rated at 105 amps, providing charging output for the boat's battery and electrical systems.

What is the part number for this Sierra alternator? The part number is 18-6408, a Sierra branded marine alternator.

What boats or engines is the 18-6408 alternator designed for? This alternator is designed for Mercruiser applications, making it suited to boats running Mercruiser powertrains that need a 105 amp charging unit.

How much does the Sierra 18-6408 alternator weigh? It weighs 9.3 pounds.

What are the dimensions of the 18-6408 alternator? The unit measures 8 x 8 x 7 inches.

What finish does the alternator housing have? The Sierra 18-6408 has a machined exterior finish.

Is the Sierra 18-6408 a genuine Sierra part? Yes, the 18-6408 is a genuine Sierra branded 105 amp marine alternator.

What is the UPC for the Sierra 18-6408 alternator? The UPC for this Sierra alternator is 808282378905.

Can the 18-6408 alternator handle extra onboard electronics? With a 105 amp rating, the Sierra 18-6408 supports demanding electrical loads from additional electronics, lighting, or accessories on Mercruiser powered boats.

What is included when purchasing the 18-6408? The purchase includes the Sierra 18-6408 alternator unit itself, part number 18-6408.