Sierra 18-55505 Outboard Starter for Mercury Outboard Engines, 12 Volt DC

The Sierra 18-55505 is a 12 volt DC outboard starter built for Mercury outboard engines, engineered to hold up in harsh marine environments where moisture and vibration cause standard starters to fail early. It features OEM-upgraded internals, including a strengthened connection between the solenoid and the commutator brushes, an upgraded planetary seal, and a robust clutch gear spring, all aimed at extending service life and improving cranking reliability season after season.

A redesigned solenoid uses higher quality materials for consistent performance and includes an increased battery stud length that makes wiring and installation easier at the bench or in the boat. To fight the water intrusion that plagues outboard starters, Sierra integrated seals at key points in the housing along with a one-way duckbill moisture valve and relief cuts, so any water that does get in has a path out before it can start corroding internal components. The starter carries a painted surface finish and an improved housing for added corrosion resistance in salt or fresh water use.

Rated at 1.4 kW and weighing 7.7 pounds, the Sierra 18-55505 is designed as a direct functional upgrade over standard replacement starters for Mercury outboard engines.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-55505
• Item Type: Starter
• Application: Mercury outboard engines
• Voltage: 12 Volts (DC)
• Wattage: 1.4 kW
• Phase Type: Single Phase
• Material: Plastic
• Weight: 7.7 pounds
• UPC: 808282379094

Frequently Asked Questions

What is the Sierra 18-55505? It is a 12 volt DC outboard starter built by Sierra for Mercury outboard engines, part number 18-55505.

Will the 18-55505 fit my Mercury outboard? The Sierra 18-55505 is designed for Mercury outboard engines; check your existing starter's part number or your engine's parts diagram against 18-55505 to confirm an exact match before ordering.

How much does this starter weigh? The Sierra 18-55505 outboard starter weighs 7.7 pounds.

What voltage is the Sierra 18-55505 starter? It is a 12 volt DC starter rated at 1.4 kW.

What makes this starter better than a standard replacement? The 18-55505 includes OEM-upgraded features not found on basic replacement starters: a strengthened solenoid-to-commutator brush connection, an upgraded planetary seal, and a reinforced clutch gear spring for longer service life.

How does the Sierra 18-55505 handle water intrusion? Seals are placed at key points throughout the housing, and a one-way duckbill moisture valve along with relief cuts lets any water that gets in drain back out before corrosion can start.

What is the housing made of? The Sierra 18-55505 starter has a plastic housing component with a painted surface finish for added corrosion resistance.

Is installation different from a standard starter? The 18-55505 has an increased battery stud length compared to standard designs, which Sierra built in specifically to make cable connection and installation easier.

What is included when I order the 18-55505? You receive one complete Sierra 18-55505 outboard starter assembly, ready to install.

Is the Sierra 18-55505 a genuine Sierra part or aftermarket? The 18-55505 is manufactured and sold under the Sierra brand as an OEM-upgraded replacement starter, not a generic third-party clone.

Does the 18-55505 include the solenoid? Yes, the Sierra 18-55505 starter comes with its solenoid attached as part of the complete starter assembly, featuring Sierra's improved solenoid design.