Sierra 18-99540 Spark Tester with Adjustable Gap

The Sierra 18-99540 Spark Tester is an essential diagnostic tool for testing ignition systems on marine engines, outboards, and small engines. This professional-grade spark tester features an adjustable gap section that allows you to simulate various load conditions and verify spark strength across different engine types.

Key Features:

• Adjustable gap design for testing different spark intensities and ignition system performance
• Inline configuration connects between spark plug wire and spark plug for real-time testing
• Clear visual spark indication makes it easy to diagnose ignition problems
• Durable construction designed for marine environments and harsh conditions
• Compatible with outboard motors, inboard engines, and other small engine applications

This spark tester helps quickly identify weak or missing spark conditions, making it an invaluable tool for troubleshooting hard-starting engines, misfires, and no-start conditions. The adjustable gap feature allows technicians to test ignition coil output under varying load conditions.