Yamaha - Fuel Pressure Gauge Adapter B Diagnostic Tool Adapter 90890-06946-00. Overview. When you're chasing a fuel issue, guessing doesn't get you far-you need real numbers. I've used these adapters plenty of times to hook up a gauge and see exactly what the system is doing under load. The Yamaha Fuel Pressure Gauge Adapter B 90890-06946-00 makes that connection clean and reliable without fighting fittings or leaks. It's a small tool, but it saves a lot of time when diagnosing fuel problems.. Key Features. • Accurate Diagnostic Connection - Allows proper attachment of a fuel pressure gauge for testing.. • Yamaha-Specific Fitment - Designed to match factory fuel system ports and threads.. • Leak-Resistant Design - Provides a secure seal during pressure testing.. • Supports Efficient Troubleshooting - Helps identify fuel delivery issues quickly and clearly.. • Durable Tool Construction - Built to handle repeated use in marine service environments.. Engine & Boat Compatibility. The Yamah