Sierra 18-28086 Spark Plug Wire Set for 6-Cylinder Mercury Outboard Engines

The Sierra 18-28086 Spark Plug Wire Set is a replacement ignition wire set built for 6-cylinder Mercury outboard engines. Each set is packaged complete and ready to install, restoring reliable spark delivery to engines with worn, cracked, or deteriorated factory wires. The wires use a copper core for consistent electrical conduction along with polyvinyl chloride (PVC) insulation that stands up to engine-bay heat, moisture, and vibration. Boot-style connectors on the wire ends provide a secure, snug fit at the spark plug and coil connection points, helping prevent misfires caused by loose or arcing connections.

Because ignition wires degrade over time from heat cycling and exposure to fuel and oil residue, replacing the full set together (rather than one wire at a time) helps ensure even resistance and consistent spark across all cylinders. The 18-28086 set is sized specifically for 6-cylinder applications, matching the cylinder count of the Mercury outboard engines it is designed to service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-28086
• Number of Cylinders: 6
• Application: Mercury outboard engines
• Material: Copper (core), Polyvinyl Chloride (PVC) (insulation)
• Connector Type: Boots
• Number of Items: 1 (complete set)
• Item Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 0.78125 pounds
• UPC: 808282341459

Fitment

Fits 6-cylinder Mercury outboard engines.

Frequently Asked Questions

What engines is the Sierra 18-28086 spark plug wire set designed for? The 18-28086 set is built for 6-cylinder Mercury outboard engines, matching the cylinder count and ignition layout of those engines.

How many cylinders does the 18-28086 wire set cover? Six. The set is sized for 6-cylinder engine applications, providing one wire per cylinder as a complete set.

What material are the wires made of? The 18-28086 spark plug wires use a copper core for electrical conduction, wrapped in polyvinyl chloride (PVC) insulation for protection against heat and moisture in the engine bay.

What type of connector do the wires use? Boot-style connectors are used on the Sierra 18-28086 wire set for a secure fit at the spark plug and coil connection points.

Is this a full set or a single wire? The 18-28086 is sold as one complete set covering all 6 cylinders, not as an individual replacement wire.

Does the 18-28086 set include the spark plugs themselves? No, this is an ignition wire (lead) set only; spark plugs are not included.

How much does the Sierra 18-28086 wire set weigh? It weighs 0.78125 pounds as packaged.

What are the packaged dimensions of the wire set? The listed item dimensions for the Sierra 18-28086 are 0.39 x 0.39 x 0.39 inches.

Is the Sierra 18-28086 a genuine manufacturer part? Yes, it is a genuine Sierra part identified by UPC 808282341459.

Why replace all the ignition wires at once instead of just the failed one? Replacing the full 18-28086 set keeps resistance and spark strength consistent across all 6 cylinders, since wires age and degrade at similar rates when exposed to the same heat and vibration.

How do I know if the 18-28086 is the correct wire set for my boat? Confirm your outboard is a 6-cylinder Mercury engine, since the 18-28086 set is matched to that cylinder count.