Sierra Spark Plug Wire 18-99314, 24 Inch Single Boot with Screw Terminal

The Sierra 18-99314 is a 24 inch single spark plug wire built for marine engine ignition systems that use a screw terminal connection. It is designed as an individual replacement wire rather than a full ignition set, making it a practical option when only one wire in the harness has failed or shows signs of wear, cracking, or arcing. The wire comes fitted with a boot on one end for a secure connection at the spark plug and a screw terminal at the opposite end, allowing it to be wired directly into the ignition system without needing a separate connector.

Using an individual replacement wire like this one lets boat owners and marine technicians address a single bad connection without replacing an entire wire set, saving on both parts cost and labor. The screw terminal design is intended for straightforward installation, and the 24 inch length is sized to reach typical marine engine spark plug locations from the distributor or ignition coil area. This part is sold under the Sierra brand and is intended for marine ignition applications where a dependable, properly insulated plug wire is essential for consistent spark delivery and reliable engine starting and running performance.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99314
• Product Name: Spark Plug Wire
• Length: 24 inches
• Terminal Type: Screw terminal
• Boot Configuration: Single booted (one boot end)
• Weight: 0.14375 pounds
• Category: Specialty Tools

Frequently Asked Questions

How long is the Sierra 18-99314 spark plug wire? The Sierra 18-99314 spark plug wire measures 24 inches in length.

What kind of terminal does this spark plug wire use? It has a screw terminal on one end, allowing it to be wired directly into a marine ignition connection without a separate plug-in connector.

Does the Sierra 18-99314 come with one boot or two? This is a single booted wire, meaning it has one boot fitted at the spark plug end and a screw terminal at the other end rather than a boot on both ends.

Is the 18-99314 sold as a single wire or a full set? The 18-99314 is sold as a single spark plug wire, not a complete ignition wire set, so it is suited to replacing one damaged or worn wire at a time.

What brand makes part number 18-99314? Part number 18-99314 is manufactured by Sierra.

How much does this spark plug wire weigh? The Sierra 18-99314 spark plug wire weighs 0.14375 pounds.

What is the 18-99314 used for? It is used as a replacement spark plug wire in marine engine ignition systems, carrying spark from the ignition source to a spark plug via a screw terminal connection.

Can I replace just one spark plug wire instead of the whole harness? Yes, the Sierra 18-99314 is designed for exactly that purpose, letting you swap out a single 24 inch wire with a screw terminal instead of replacing an entire ignition wiring set.

Why would a screw terminal wire be preferred over a snap-on boot wire? A screw terminal, as used on the Sierra 18-99314, provides a mechanically fastened connection point, which some marine ignition setups require in place of a push-on boot connector.

What category does this product fall under? The Sierra 18-99314 is categorized as a specialty tool item related to marine ignition wiring.