2001-2002 Yamaha 50HP F50Z/T50Z Ouboard 4-stroke engines service manual, Page 129Get this manual
Troubleshooting Symptom: Engine can run, but engine speed will not increaseOverheat warning indicator is onOil pressure warning indicator is onWarning indicator is on and buzzer is sounding Check the water cooling system Check the lubricating systemCheck the water inlet for clogs or debrisCheck that cooling water is discharged from the pilot water outlet
Clogs or debris? Yes Clean the water inlet