Sierra MP40960 Emergency Cut-Off Switch, Universal Fit, Interchangeable with Sea-Dog 420486-1

The Sierra MP40960 is a universal-fit emergency cut-off switch (kill switch) built to shut down the engine ignition the instant its lanyard is pulled free, whether the operator falls overboard or is thrown from the helm. It works with either conventional or magneto ignition systems, making it a straightforward upgrade or replacement for boats, personal watercraft, and other small-craft helms that use a pull-cord kill switch.

The switch body offers four terminals, letting the installer wire it for either a normally open or a normally closed circuit depending on how the ignition system needs to be interrupted. The housing is sealed against moisture, which helps prevent corrosion at the terminals and keeps the connection reliable in a wet cockpit environment, and the design makes re-connecting the lanyard after use quick and simple. It ships in white to blend with light-colored helm panels.

Because the lanyard itself wears out with repeated use long before the switch body does, Sierra sells a dedicated replacement lanyard, part number MP40980, so the switch can be kept in service without replacing the whole unit. The MP40960 is also a direct functional match for the Sea-Dog 420486-1 emergency cut-off switch, giving boat owners a drop-in option if that part is what their helm currently uses.

Specifications

• Brand: Sierra
• Manufacturer Part Number: MP40960
• Product Type: Emergency Cut-Off Switch
• Terminals: 4-terminal design, selectable normally open or normally closed circuit
• Ignition Compatibility: Conventional or magneto ignitions
• Color: White
• Item Dimensions: 3.5 x 2.13 x 9 inches
• Weight: 0.18 pounds
• Fit Type: Universal fit
• Replacement Lanyard: MP40980
• UPC: 808282367183

Fitment

Universal fit for small-craft helms using a pull-lanyard emergency cut-off switch; not limited to a specific engine make, horsepower, or model.

Replaces (OEM)

• Sea-Dog 420486-1

Frequently Asked Questions

What is the Sierra MP40960 used for? The MP40960 is an emergency cut-off switch (kill switch) that shuts down the boat's ignition the moment its lanyard is pulled, protecting against an unmanned runaway boat if the operator falls or is thrown from the helm.

Will the MP40960 fit my boat? Yes, the MP40960 is a universal-fit emergency cut-off switch designed to work across small-craft helms rather than being limited to one specific boat make or engine model.

Does the MP40960 work with a magneto ignition? It works with either conventional or magneto ignition systems, so it can be wired into either type without needing a different switch.

Is the Sierra MP40960 wired as normally open or normally closed? The switch has 4 terminals that allow it to be wired for either a normally open or a normally closed circuit, depending on what the boat's ignition system requires.

What are the dimensions of the MP40960 emergency cut-off switch? The MP40960 measures 3.5 x 2.13 x 9 inches and weighs 0.18 pounds.

Is the Sierra MP40960 equivalent to a Sea-Dog switch? Yes, the MP40960 is interchangeable with the Sea-Dog 420486-1 emergency cut-off switch, so it can be used as a replacement where that part number is specified.

What color is the MP40960 switch? It is finished in white, which suits light-colored helm panels.

Can the lanyard on the MP40960 be replaced separately? Yes, the lanyard wears out before the switch body does, and Sierra part MP40980 is the designated replacement lanyard for the MP40960 switch.

Does the MP40960 resist moisture at the helm? The switch is sealed out from moisture at its connections, which helps prevent corrosion and makes reconnecting the lanyard easier after it has been pulled.

What comes with the Sierra MP40960? The MP40960 includes the switch body with its straight lanyard attached; the separate replacement lanyard, MP40980, is sold on its own when the original wears out.

Is this a genuine Sierra part or an aftermarket copy? The MP40960 is a genuine Sierra International emergency cut-off switch, not a generic aftermarket copy.