2009-2010 Suzuki DF70A DF80A DF90A Outboard Service Manual, Page 181Get this manual
Power Unit Cooling System:
Diagnostic Information and Procedures
Powerhead Cooling System Diagnosis
Condition Overheating powerhead Possible cause Water inlet screen obstructedWater passage obstructedPump plate not sealingWater pump impeller damageWater pump housing andor plate wornWater pump housing seal wornWater tube grommet damagedThermostat damageddefectiveWater pressure valve damageddefectiveThermostat damageddefectiveZ9J0111604001
CorrectionReference Item CleanClean or replaceCheck and repairReplaceReplaceReplaceReplaceReplaceReplaceReplace
Overcooling powerhead
Service Instructions
Thermostat Removal and Installation