Yamaha GP1800R: Overheat Warning and Limp Mode

A temperature warning on the GP1800R means: stop and clarify, do not ride on. M-JET DIAGNOSTIC shows you whether the heat is real or a sensor reports wrongly.

What you compare

• Engine temperature (code 15) and exhaust manifold water temperature (code 65)
• Thermo switch and oil pressure switch in the switch status
• Battery voltage while riding
• Curve from idle to full load

Cavitation and inlet

In forums, insufficient water supply is often named for overheating messages: foreign objects in the inlet or cavitation of the pump. Then the values rise plausibly. If a single sensor shows outliers instead, its wire is suspect. Never run the engine on land without a water supply, and do not ride on with real overheating. The rule of thumb from forums: in most cases a flow problem is behind it, such as a clogged exhaust water hole, intake grate or a chipped impeller, and only then a defective sensor. If both temperature values in the app look normal despite the alarm, the thermo switch is suspect.

Related topics

• Yamaha GP1800R: Unstable Idle and Starting Problems
• Yamaha GP1800R SVHO: Power Missing, Check Intake Pressure
• Yamaha WaveRunner Overheating and Temperature Sensor
• 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.