Yamaha FX SVHO: RPM Drops to About 5000 After 20 to 30 Minutes

A forum question: an FX Cruiser SVHO (2015) runs normally for the first minutes, then after 20 to 30 minutes the RPM drops to 5000 and lower, and there is no alarm. That is a case for a test ride with M-JET DIAGNOSTIC.

What you record

• Engine temperature (15) and exhaust manifold water temperature (65)
• Intake air temperature (23) and intake pressure (29)
• Throttle valve angle against throttle lever position
• Battery voltage and ignition timing

Why the delay helps

A problem that only occurs after half an hour has something to do with heat or load. If intake air temperature rises steadily, the control unit pulls power back. If voltage falls, it can be the charging system or contacts. If the throttle valve no longer follows the lever, a sensor is suspect. The recording shows the value that tips before the drop, so you do not have to guess. Supercharged engines also suffer from heat soak: if the intake air temperature rises, power is lost, even without a fault code.

Related topics

• Yamaha FX SVHO: RiDE, SCU and RPS Report Faults
• Yamaha FX SVHO Code 63: Intake System Reports Irregular Intake Air
• Yamaha WaveRunner Engine Warning Lit
• Diagnostics and fault codes for your Yamaha model
• All Yamaha WaveRunner diagnostics topics

Everything runs via app over Bluetooth, for Yamaha WaveRunners from model year 2002 to today. Learn more about the M-JET DIAGNOSTIC for Yamaha WaveRunner.