Sierra Switch Box 18-99218 for Mercury Mariner 2-Cylinder Outboard Engines

The Sierra 18-99218 is a switch box built for Mercury Mariner 2-cylinder outboard engines. The switch box is a core ignition component that manages spark timing and power delivery to the engine, and this unit is manufactured to serve as a direct replacement on 2-cylinder Mercury Mariner powerheads. Sierra produces this part under its own part number for boat owners and marine technicians who need to replace a failed or aging switch box without sourcing directly from the engine manufacturer.

Because the switch box sits in the ignition circuit, a worn or failing unit can cause hard starting, misfiring, or a complete no-spark condition on 2-cylinder Mercury Mariner outboards. Replacing it with the correct part restores proper ignition function. This listing covers the Sierra 18-99218 specifically for 2-cylinder Mercury Mariner applications.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99218
• Product Type: Switch Box
• Engine Compatibility: Mercury Mariner 2-Cylinder Outboards
• Weight: 0.6 pounds
• UPC: 808282393878

Fitment

• Mercury Mariner 2-cylinder outboard engines

Frequently Asked Questions

What engines does the Sierra 18-99218 switch box fit? The Sierra 18-99218 is built for Mercury Mariner 2-cylinder outboard engines.

What does a switch box do on an outboard engine? A switch box is an ignition component that controls spark timing and power delivery to the engine; on 2-cylinder Mercury Mariner outboards, the Sierra 18-99218 performs this role.

How much does the Sierra 18-99218 switch box weigh? It weighs 0.6 pounds.

Is the Sierra 18-99218 an OEM or aftermarket part? It is manufactured by Sierra, an aftermarket marine parts brand, under Sierra's own part number 18-99218.

What is the UPC for the Sierra 18-99218 switch box? The UPC is 808282393878.

Will this switch box work on a 4-cylinder or 6-cylinder Mercury outboard? No, the Sierra 18-99218 is designated for 2-cylinder Mercury Mariner outboard engines.

What are symptoms of a failing switch box on a 2-cylinder Mercury Mariner outboard? Hard starting, misfiring, or a no-spark condition can indicate a failing switch box; the Sierra 18-99218 is designed to replace the unit on 2-cylinder Mercury Mariner engines.

Does the Sierra 18-99218 come with mounting hardware or wiring instructions? The listing does not specify included accessories beyond the switch box unit itself.

Is the Sierra 18-99218 sold as a single unit? Yes, it is sold as a single switch box unit for 2-cylinder Mercury Mariner outboards.

Who manufactures the 18-99218 switch box? Sierra manufactures the 18-99218 switch box for 2-cylinder Mercury Mariner outboard applications.