Watertight 3-Position Ignition Starter Key Switch (Brass, 15A, 3 Terminals + Cap)

This watertight 3-position brass ignition switch is a classic solution for a boat’s starting system. It’s designed for scenarios requiring the three basic functions – engine shut-off, ignition on, and starter engagement – without an additional accessory position. This makes it straightforward and user-friendly, similar to a car ignition key but with reinforced construction for marine use.

Construction and durability: The brass housing and internal components ensure reliable operation in wet and salty conditions. Brass offers excellent corrosion resistance, and the electrical terminals provide stable connectivity for high current (up to 15A). The switch is equipped with a rubber protection cap that shields the key slot from water ingress, dust, and salt air. Even in heavy rain or spray, the electrical portion of the switch remains dry, preventing potential short circuits or difficulty turning the key due to salt build-up.

Functionality:

• In the “Off” position, the engine is stopped and the engine’s electrical system is unpowered. The key can be removed – providing security against unauthorized starting or theft.
• In the “On” (Ignition) position, power is supplied to the engine’s ignition system, fuel pump (if applicable), and dashboard indicators. The boat is now ready to start.
• Turning to the “Start” position engages the starter motor – this position is momentary (spring-loaded to return to “On” when released), cranking the engine until it fires up.

After a successful start, the key remains in the “On” position with the engine running, and the rubber cap envelops the inserted key, preventing water from entering the keyhole while underway.

Installation and compatibility: The mounting hole diameter is standard (≈19 mm or 3/4"), meaning this switch can replace most factory boat ignition switches without modifications. It secures tightly with the included backing nut. The rear 3 terminals are standardly labeled: “B” for Battery (input from the battery/12V feed), “I” or “IGN” for Ignition (output to ignition coil and any circuits powered in run position), and “S” for Starter (output to the starter solenoid). This makes wiring straightforward and almost foolproof for a technician or DIY installer.

Applications: This model is suitable for a wide range of boats and engines. It can be used for outboard engines (e.g., on fishing boats, RIBs, rigid inflatables) as well as inboard engines on small yachts and runabouts that do not require a separate accessory position. It’s commonly installed on open helm stations, center consoles of powerboats, cockpit panels on sailing yachts, and other locations where the switch may be exposed to the elements.

Why choose this switch:

• Ease of use: No unnecessary positions – just the essential steps for safe engine start and stop. This simplifies training new boat operators and reduces confusion.
• Enhanced durability: The brass, watertight switch provides years of reliable service. Unlike automotive switches, marine ignitions face vibration, salt, and temperature swings – this model is built for those conditions.
• Safety: The waterproofing means that even if the switch is mounted horizontally or facing upwards, rainwater will not seep in. This avoids electrical failures on your boat, especially critical when you’re out at sea.
• Compact form: Along with its cap and key, the unit is compact and doesn’t take up much space behind the dash. This is important for small consoles where depth is limited.

Two matching keys are included with the switch. This gives you a spare – you can keep one in a safe place or give it to a co-captain. With the watertight 3-position brass ignition switch, every turn of the key brings peace of mind: your engine will start reliably, and the switch itself stands up to the weather’s worst.