Yamaha FX HO Won't Start: Check Relays and Fuel Pump

The FX HO does nothing at the start or cranks without firing. M-JET DIAGNOSTIC first checks what the control unit knows about relays and switches, then lets pump, coils and injectors respond.

The order

• Voltage during the start attempt
• Main relay, ETV relay and fuel pump relay in the switch status
• Kill switch and start switch in the switch status
• Activate pump, four ignition coils and four injectors

What you derive from it

If a relay signal is missing, you look before the component: fuse, wire or switch. If the pump runs but nothing fires, check camshaft and pulser coil messages in the memory. If only one cylinder does not respond, that cylinder's component is the first candidate. That narrows down in a few minutes what otherwise takes hours.

Related topics

• Yamaha FX HO: Power Loss, Knock Sensor and Intake Pressure
• Yamaha FX HO: Reset the Maintenance Warning and Check Hours
• Yamaha WaveRunner Won't Start: Diagnostics
• 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.