Sierra 18-5775-1 Switch Box, Replaces Mercury Marine 332-7778A12, Fits 3 and 6-Cylinder Outboards with ADI Ignition

The Sierra 18-5775-1 is an ignition switch box built for 3 and 6-cylinder outboard engines equipped with ADI (Automotive Distributorless Ignition) systems. It serves as the electronic control unit that manages spark timing for the ignition system, and it is engineered to meet or exceed the performance of the original equipment part it replaces.

The switch box is housed in a durable plastic enclosure finished in silver, with a compact 5.5 x 5.25 x 3.5 inch footprint that fits into the same panel-mount location as the original unit. It uses a rear connector for wiring and is rated for 18 Amps with a 1-way circuit and a single switch position, matching the electrical demands of the outboard ignition systems it is designed to serve.

This switch box is a direct interchange for a wide range of OEM and aftermarket part numbers used across multiple outboard brands, including CDI, Chrysler/Force/US Marine, Mallory, and Mercury Marine (including Mercury Race Outboard and Mercury Sport Jet applications). This broad cross-reference coverage makes it a practical replacement option for boat owners and technicians servicing older ADI-equipped outboards where locating an exact OEM part can be difficult.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5775-1
• Category: Mercury Outboard Switch Box
• Switch Type: Ignition Switch Box
• Current Rating: 18 Amps
• Circuit Type: 1-way
• Number of Positions: 1
• Controller Type: Push Button
• Mounting Type: Panel Mount
• Connector Type: Rear Mount
• Material: Plastic
• Color: Silver
• Item Dimensions: 5.5 x 5.25 x 3.5 inches
• Weight: 1.02 pounds
• UPC: 808282392604
• Compatible Engines: 3 and 6-cylinder outboards with ADI ignition systems

Fitment

Fits 3 and 6-cylinder outboards with ADI ignition systems.

Replaces (OEM)

• 114-7778
• 332-7778A12
• 9-25100
• 332-5524A1
• 332-7778A1
• 332-7778A3
• 332-7778A6
• 332-7778A7
• 332-7778A9
• F749301
• F7778A9

Frequently Asked Questions

What engines does the Sierra 18-5775-1 switch box fit? The 18-5775-1 fits 3 and 6-cylinder outboards equipped with ADI ignition systems.

Is the 18-5775-1 compatible with Mercury Marine switch boxes? Yes, it interchanges with Mercury Marine part numbers 332-5524A1, 332-7778A1, 332-7778A12, 332-7778A3, 332-7778A6, 332-7778A7, 332-7778A9, F749301, and F7778A9.

Does this switch box replace a CDI or Mallory unit? Yes, the Sierra 18-5775-1 interchanges with CDI 114-7778 and Mallory 9-25100 in addition to Mercury Marine and Chrysler/Force/US Marine numbers.

What is the current rating of the 18-5775-1? It is rated at 18 Amps.

What size is the Sierra 18-5775-1 switch box? It measures 5.5 x 5.25 x 3.5 inches.

How much does the 18-5775-1 weigh? The switch box weighs 1.02 pounds.

What is the switch box housing made of? The 18-5775-1 has a plastic housing finished in silver.

How does the 18-5775-1 mount and connect? It uses a panel mount design with a rear connector for wiring.

Is the 18-5775-1 a genuine Sierra part or an aftermarket copy? It is a genuine Sierra switch box built to meet or exceed the original equipment part it replaces.

What comes in the box when I order the 18-5775-1? One Sierra 18-5775-1 switch box is included.

Will the 18-5775-1 work on a Mercury Race Outboard or Mercury Sport Jet engine? Yes, it interchanges with Mercury Race Outboard 332-7778A12 and 332-7778A3, and Mercury Sport Jet 332-7778A12.

How many switch positions does the 18-5775-1 have? It has a 1-way circuit with a single switch position, controlled by a push button.