BlueStars 12V Starter Solenoid Relay for Mercury Outboard — 89-817109A3 Model, Heavy-Duty Corrosion-Resistant

BlueStars 12V starter solenoid relay 89-817109A3 is a direct-replacement electromagnetic switch that routes battery power to your Mercury outboard starter for reliable engine cranking.

This heavy-duty 12V starter solenoid is engineered to match exact Mercury and compatible part numbers, offering corrosion-resistant materials and high-temperature copper windings to maintain consistent conductivity in marine conditions. It’s built to stand up to oil, salt spray, and vibration while delivering fast engagement and clean disengagement once your engine fires. The unit replaces common OEM codes and fits a wide range of Mercury Marine, Force Marine, Sierra, and other outboards across multiple model years.

Will this relay fit my Mercury outboard model?

The BlueStars 89-817109A3 is designed as a plug-and-play replacement for multiple Mercury part numbers and several aftermarket equivalents. Check your original part number or the engine’s service manual to confirm compatibility. If your engine uses the listed terminal sizes and mounting pattern, this solenoid will match physical and electrical connections.

• Replaces Mercury 89-817109A1/A2/A3 and 87-803632T among others
• Compatible with Force Marine and many Mercury model ranges (1996–newer where specified)
• Standard 5/16-18 power terminals and OEM mounting footprint

How does this solenoid improve starting performance?

By providing a low-resistance, high-current path from the battery to the starter motor, the solenoid reduces voltage drop and helps the starter receive full power for quicker cranking. Its copper coil and anti-oxidizing contacts maintain a strong magnetic field for dependable engagement. After the engine starts, the solenoid opens the circuit to stop unnecessary battery drain and wear on the starter.

• Copper windings and contacts for consistent conductivity
• Inner 180°C copper coil resists heat-related degradation
• Flame-retardant ABS housing protects internal parts in harsh environments

What are the durability and safety features?

The housing is molded from high-insulation ABS that resists oil, dust, chemicals, and impact, helping prolong service life in marine applications. Internal components feature anti-oxidation treatments and heat-resistant specifications so the relay holds up under repeated engagement cycles. BlueStars also backs the part with a lifetime protection policy for manufacturing defects.

• ABS plastic enclosure with flame-retardant properties
• Anti-corrosion copper contacts and treated windings
• Rated for marine exposure and operational heat up to 180°C in the coil

How do I install and maintain the solenoid?

Installation typically involves removing the old solenoid, transferring battery and starter cables to the matching terminals, and securing the unit to the existing mount. Use correct torque on power studs and ensure all connections are clean and tight. Periodic inspection for terminal corrosion and wiring integrity will maximize life and prevent intermittent starts.

• Matches OEM terminal layout—swap directly for quick replacement
• Tighten 5/16-18 studs to manufacturer torque specs; avoid over-tightening
• Inspect terminals and apply dielectric grease to resist corrosion

Who is this for: Boaters, marine mechanics, and DIY enthusiasts needing a dependable starter relay for Mercury and compatible outboards will find this BlueStars solenoid suited to frequent use and saltwater exposure. It’s ideal when you require a direct-fit replacement of part numbers like 89-817109A2/A3, 87-803632T, or aftermarket equivalents from Sierra and Arco. Choose this unit if you want OEM-style fitment, robust electrical contacts, and a housing built to resist the marine environment while backed by lifetime protection.