Yamaha WaveRunner XLT800 (XLT-800) overheating refers to when the jet-ski’s engine temperature becomes too hot. Serious mechanical damage can occur if the Yamaha XLT800 engine overheats for too long, such as cylinder head damage, head gasket damage or warpage to the cylinders.
It’s important to identify the causes to an overheating issue and correct it before potential damage occurs. Use the following information to identify possible causes. Check for one or more possible malfunctions:
- Cooling passages in pump restricted. Inspect the screen and passages.
- Pump housing or impeller damaged.
- Pump housing passage plugs are possibly missing.
- Thermostat or pop-off valve possibly restricted.
- Sand or debris restricting cooling water passages in engine.
- Damaged or loose cooking hoses or clamps.
- Collapsed or restricted exhaust pip or hose.
It’s possible other less common reasons could be causing the Yamaha XLT-800 to overheat but these are the most probable causes. It’s highly recommend you refer to the download factory service manual for additional information regarding overheating issues