Sierra Neon Spark Tester 18-99527, Inline 1-Cylinder Spark Checker for PWC Engines

The Sierra Neon Spark Tester (18-99527) is an inline, single-cylinder tool for checking spark on a running engine, built with personal watercraft (PWC) applications in mind. It installs in-line with the spark plug lead so you can visually confirm the ignition system is firing while the engine runs, without pulling the plug or guessing at a weak connection. The tester uses a sealed neon design, which adds a margin of safety by reducing the chance of igniting gas fumes that can collect in a PWC hull, an important consideration given how enclosed the engine compartment is on most personal watercraft. Because it checks spark under actual running conditions rather than a static bench test, it gives a more realistic read on ignition performance, helping narrow down hard-starting, misfire, or no-spark complaints to the ignition side of the engine before moving on to plugs, coils, or the CDI/ignition module. It is sized for a single cylinder, so multi-cylinder engines are checked one plug lead at a time. This is a diagnostic accessory meant for technicians and owners doing their own ignition troubleshooting on outboard and PWC engines.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99527
• Product Name: Neon Spark Tester - 1 Cyl.
• Design: Sealed, inline neon spark tester
• Cylinder Capacity: 1 cylinder
• Primary Application: Personal watercraft (PWC) ignition systems
• Use Case: Checking spark on a running engine
• Package Dimensions: 7.83 x 4.45 x 2.32 inches
• Weight: 0.3 pounds
• UPC: 808282394844

Frequently Asked Questions

What does the Sierra 18-99527 spark tester do? It installs inline with a spark plug lead so you can visually confirm the ignition system is firing while the engine is running, making it a quick way to check for spark without disconnecting the plug.

Is this tester safe to use on a personal watercraft? Yes, the 18-99527 has a sealed neon design intended to reduce the chance of igniting gas fumes, which is a particular concern in the enclosed hull of a PWC.

How many cylinders can this tester check at once? The 18-99527 is a 1-cylinder tester, so on a multi-cylinder engine you check one plug lead at a time.

Can I use this while the engine is running? Yes, the Sierra 18-99527 is designed to check spark on a running engine, giving a real-time read on ignition performance rather than a static bench check.

What are the package dimensions of the 18-99527 spark tester? The packaged unit measures 7.83 x 4.45 x 2.32 inches.

How much does the spark tester weigh? The Sierra 18-99527 Neon Spark Tester weighs 0.3 pounds.

What engines is the 18-99527 intended for? It is intended for personal watercraft (PWC) engines, where checking spark safely in a confined hull space matters most.

Does the tester require any tools to install? It is an inline tester that connects in the spark plug lead circuit; no additional tools are needed to place it in line for a spark check.

Why use a sealed neon design instead of an open spark gap tester? The sealed design on the 18-99527 lowers the risk of sparking near open gas fumes, which is safer than an exposed spark gap when working around a PWC engine compartment.

What UPC is associated with this product? The Sierra Neon Spark Tester, part number 18-99527, carries UPC 808282394844.