7-Inch Spark Plug Wire (8 mm) – Mercury/Mariner 2-Stroke Outboard Replacement
7-Inch Spark Plug Wire (8 mm) – Mercury/Mariner 2-Stroke Outboard Replacement is backordered and will ship as soon as it is back in stock.
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7-Inch Spark Plug Wire (8 mm) – Mercury/Mariner 2-Stroke Outboard R...
7-Inch Spark Plug Wire (8 mm) – Mercury/Mariner 2-Stroke Outboard Replacement is backordered and will ship as soon as it is back in stock.
Product Details
This 7-inch, 8 mm spark plug wire is an aftermarket replacement lead for compatible Mercury and Mariner 2-stroke outboard ignition systems. It transfers high-voltage ignition energy to the spark plug through a molded boot and terminal connection.
The wire is intended for applications that use a 7-inch, 8 mm lead. Because ignition-wire length, terminal style, boot design, and routing can vary between engines, compare the original wire carefully before ordering.
- 7-inch overall wire length for applications requiring this specific lead size.
- 8 mm silicone outer jacket for heat and moisture resistance.
- Molded ignition boot and terminal ends for a secure connection.
- Suitable for direct replacement when the original wire has the same length and connection configuration.
- Aftermarket component; not manufactured by Mercury Marine.
Part Number Information
Catalog references distinguish this 7-inch, 8 mm wire from other Mercury/Mariner ignition leads. The Mercury reference 84-813715A1 is listed with separate 9-inch wire applications and should not be used to identify this 7-inch wire.
| Reference Type | Reference | Application Note |
|---|---|---|
| Catalog description | 7-inch Spark Plug Wire (8 mm) | Match the original wire length and terminal configuration. |
| Catalog-listed 9-inch lead reference | 84-813715A1 | Not identified as the 7-inch wire; do not substitute by number alone. |
Engine & Model Compatibility
This wire is for compatible Mercury/Mariner 2-stroke outboard ignition applications that use a 7-inch, 8 mm spark plug lead. A specific engine model cannot be confirmed from the wire length alone.
| Brand | Engine Type | Wire Requirement | Fitment Confirmation |
|---|---|---|---|
| Mercury / Mariner | Compatible 2-stroke outboard ignition systems | 7-inch, 8 mm spark plug wire with matching boot and terminal ends | Confirm against the original wire, engine serial number, and ignition-system configuration before installation. |
Important: Do not rely on horsepower, model family, or a similar-looking wire alone. Some Mercury/Mariner engines use different wire lengths, conductor types, or terminal arrangements within the same horsepower range.
Technical Specs
- Product Type
- Spark Plug Wire
- Length
- 7 inches
- Nominal Jacket Size
- 8 mm
- Application
- Compatible Mercury/Mariner 2-stroke outboard ignition systems
- Installation
- Direct replacement when dimensions and connection ends match
- Material
- Silicone outer insulation with ignition-wire terminal components
- Connection
- One ignition terminal end and one spark plug boot end; verify the configuration before purchase
- Color
- Black
- Product Status
- Aftermarket replacement, not OEM
What’s in the Box
- 1 x 7-inch, 8 mm spark plug wire
No spark plug, ignition coil, distributor, switch box, or additional wires are included.
Installation Notes
- Turn the engine off, allow it to cool completely, and disconnect the battery before servicing the ignition system.
- Record the original wire routing and compare the replacement wire with the removed wire before installation.
- Remove the spark plug boot by twisting and pulling on the boot, not the wire.
- Disconnect the opposite terminal from the ignition coil, distributor, or other ignition component.
- Install the replacement wire in the same direction and routing as the original.
- Seat the ignition terminal fully on its connection point and press the spark plug boot firmly onto the spark plug.
- Keep the wire away from sharp edges, hot exhaust components, and moving parts.
- Reconnect the battery and inspect the installation before starting the engine.
Troubleshooting & FAQ
How do I confirm that this wire will fit my engine?
Measure the original wire, confirm that it is approximately 7 inches long and uses an 8 mm jacket, and compare both terminal ends and boot shapes. Also verify the engine serial number and ignition-system diagram when available. A similar horsepower rating does not by itself confirm fitment.
Is this the same as the 9-inch wire listed with Mercury reference 84-813715A1?
No. The catalog information separates the 7-inch, 8 mm wire from 9-inch wire applications associated with that reference. Do not use the 9-inch reference to identify or substitute for this 7-inch wire.
What are common signs of a failing spark plug wire?
Common symptoms include misfire, rough running, hard starting, reduced power, poor acceleration, and visible cracking, burning, corrosion, or looseness at either connection.
Can I test the old wire?
Inspect the insulation and terminals first. You can also use a multimeter to check continuity from end to end. An open circuit, unstable reading, or clear physical damage indicates that the wire should be replaced. Follow the engine manufacturer’s service specifications for resistance limits.
Is this an OEM Mercury part?
No. This listing is for an aftermarket replacement wire. It is intended to replace a matching original wire when the length, jacket size, boot, and terminal configuration are the same.
How quickly will my order ship?
Available shipping methods, delivery estimates, and costs are shown at checkout based on your destination and the shipping service selected.
Safety & Important Info
- Verify the original wire length, 8 mm jacket size, terminal ends, boot shape, and engine serial-number application before ordering.
- Do not substitute a 7-inch wire for a 9-inch or other-length lead unless the engine service information specifically permits it.
- Disconnect the battery and keep the engine off while replacing ignition components.
- Professional installation is recommended if the ignition-system configuration or fitment is uncertain.
About Sea Sierra
- Marine Replacement Parts — We supply aftermarket components for maintenance and repair applications.
- Fitment-Focused Support — Compare dimensions, connector details, and engine information before ordering.
- Global Fulfillment — Available shipping options and delivery estimates are presented at checkout.
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