Sierra Switch Box 18-99222 for Mercury Mariner 2 Cylinder Outboards 6-25 HP 1997-2006, Replaces 855713A3 855713A4

The Sierra 18-99222 switch box is an ignition control unit built to power the spark timing on 2 cylinder Mercury and Mariner outboards. It functions as the electronic switch box (ignition pack) that fires the coils in sequence, and it is designed as a direct replacement for the factory Mercury switch box on the covered engine range. Buyers replace this component when an outboard cranks but will not fire, runs on one cylinder, or shows an intermittent spark caused by a failing switch box.

This unit is built for the 2 cylinder Mercury/Mariner outboard family rated 6, 8, 9.9, 10, 15, 20 and 25 HP, covering engines from 1997 through 2006. It is a plug-in style replacement, so it is installed by disconnecting the factory harness connector, mounting the new switch box in the same location, and reconnecting the existing wiring, with no rewiring or splicing needed on a correctly matched application. Always confirm the HP, cylinder count, and model year of your specific outboard against the fitment listed here before ordering, since Mercury used different switch boxes across its outboard lineup.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99222
• Category: Mercury Outboard Switch Box
• Weight: 0.7 pounds
• UPC: 808282393892
• Cylinder Count: 2 Cylinder
• Horsepower Range: 6, 8, 9.9, 10, 15, 20, 25 HP
• Model Years: 1997-2006
• Vehicle Service Type: Outboard
• Installation Type: Plug-In
• Connector Gender: Female-to-Male
• Item Dimensions: 5 x 4 x 2 inches

Fitment

• Mercury/Mariner 2 cylinder outboards: 6, 8, 9.9, 10, 15, 20 and 25 HP, 1997-2006

Replaces (OEM)

• 855713A3
• 855713A4

Frequently Asked Questions

What does the Sierra 18-99222 switch box fit? It is built for 2 cylinder Mercury and Mariner outboards rated 6, 8, 9.9, 10, 15, 20 and 25 HP from 1997 through 2006.

Is 18-99222 a direct OEM replacement? Yes, Sierra part 18-99222 is a direct replacement switch box that crosses to OEM Mercury numbers 855713A3 and 855713A4.

How much does the switch box weigh? The Sierra 18-99222 switch box weighs 0.7 pounds.

Will this work on a 3 or 4 cylinder outboard? No. The 18-99222 switch box is designed specifically for 2 cylinder Mercury/Mariner outboards and is not intended for 3 or 4 cylinder engines.

What connector type does this switch box use? It uses a female-to-male connector and is a plug-in installation, so it connects directly into the existing outboard wiring harness.

Do I need to modify any wiring to install part 18-99222? No rewiring is needed on a correctly matched application. The switch box is a plug-in unit, so you unplug the old switch box and plug in the new one at the factory harness connector.

What are the dimensions of the switch box? The switch box measures approximately 5 x 4 x 2 inches.

What OEM part numbers does 18-99222 replace? This switch box replaces Mercury OEM numbers 855713A3 and 855713A4.

What symptoms indicate the switch box needs to be replaced? A failing switch box on a 2 cylinder Mercury/Mariner outboard can cause no-spark cranking, running on only one cylinder, or intermittent misfires; the 18-99222 switch box addresses these ignition failures.

Does the horsepower rating matter when ordering this part? Yes, confirm your outboard is one of the 6, 8, 9.9, 10, 15, 20 or 25 HP 2 cylinder models covered by the 18-99222 switch box, since Mercury used different switch boxes across its outboard range.

Is this switch box also called an ignition pack? Yes, the 18-99222 is a switch box, also referred to as an ignition pack, that controls spark timing to the coils on 2 cylinder Mercury/Mariner outboards.