Sierra 18-99244 Ignition Switch Box for Mercury/Mariner 4 and 6 Cylinder Outboard Engines

The Sierra 18-99244 is an ignition switch box built for Mercury and Mariner outboard engines, covering both 4 cylinder and 6 cylinder powerheads. It serves as the ignition control module that manages spark timing and delivery to the engine, a critical component for reliable starting and running. This switch box is designed to fit 4 cylinder Mercury/Mariner outboards rated at 50, 65, 80, and 85 HP, as well as 6 cylinder Mercury/Mariner outboards rated at 90, 100, 115, 125, 135, 140, and 150 HP. The housing is constructed of plastic and uses a spade terminal connection with a plug-in connector type, allowing it to interface with the factory wiring harness on applicable engines. It operates with a normally open contact and an ON-OFF operation mode, and is rated for a 1 kilovolt operating voltage with a 5 milliamp current rating. The unit measures 7 x 5 x 3 inches and weighs 1.8 pounds. Because ignition switch boxes are engine-specific, boat owners replacing a failed or intermittent ignition component should confirm their engine's cylinder count and horsepower rating against the fitment listed below before ordering. This part is intended as a direct functional replacement for the ignition switch box on the covered Mercury/Mariner engines.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99244
• Weight: 1.8 pounds
• Item Dimensions: 7 x 5 x 3 inches
• Material: Plastic
• Operation Mode: ON-OFF
• Contact Type: Normally Open
• Operating Voltage: 1 Kilovolts
• Current Rating: 5 Milliamps
• Connector Type: Plug In
• Terminal: Spade
• Mounting Type: Panel Mount
• Number of Positions: 6
• UPC: 808282394103

Fitment

• Mercury/Mariner 4 cylinder outboard engines, 50, 65, 80, and 85 HP, 1967-1975
• Mercury/Mariner 6 cylinder outboard engines, 90, 100, 115, 125, 135, 140, and 150 HP, 1967-1979

Frequently Asked Questions

What engines does the Sierra 18-99244 ignition switch box fit? The Sierra 18-99244 fits Mercury/Mariner 4 cylinder outboard engines rated at 50, 65, 80, and 85 HP built from 1967-1975, and 6 cylinder outboard engines rated at 90, 100, 115, 125, 135, 140, and 150 HP built from 1967-1979.

How much does the 18-99244 ignition switch box weigh? It weighs 1.8 pounds.

What are the dimensions of this ignition switch box? The Sierra 18-99244 measures 7 x 5 x 3 inches.

What material is the Sierra 18-99244 switch box made of? The housing is made of plastic.

Is the Sierra 18-99244 an ON-OFF style switch box? Yes, the 18-99244 operates in ON-OFF mode with a normally open contact type.

What voltage and current is the 18-99244 rated for? It carries a 1 kilovolt operating voltage rating and a 5 milliamp current rating.

What type of electrical connection does this switch box use? The Sierra 18-99244 uses a plug-in connector with a spade terminal, and it has 6 positions.

Does the 18-99244 fit both 4 cylinder and 6 cylinder Mercury outboards? Yes, one part number covers both the 4 cylinder engines (50, 65, 80, 85 HP, 1967-1975) and the 6 cylinder engines (90, 100, 115, 125, 135, 140, 150 HP, 1967-1979), so confirm your engine's cylinder count and horsepower before ordering.

Is this switch box mounted to a panel? Yes, the Sierra 18-99244 uses a panel mount configuration.

Will this switch box work on a Mariner-branded outboard as well as a Mercury? Yes, the 18-99244 is designed to fit both Mercury and Mariner outboard engines within the listed cylinder and horsepower ranges.

What comes with the Sierra 18-99244? The 18-99244 is supplied as a single ignition switch box unit.