2005 Yamaha F90TR 90HP Outboards Factory Service Manual, Page 206Get this manual
Electrical systems
2Connect computer to the outboard motor and use the Yamaha Diagnostic System to display the intake air temperature
Checking the oil pressure switch
1Check the oil pressure switch for continuityReplace if there is no continuity2Connect the special service tool to the oil pressure switch3Slowly operate the special service tool
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3If the ambient temperature and the displayed intake air temperature differ by more thanF), replace the sensor assemblyNOTE: Check the sensor assembly when the engine is cold
Checking the cooling water temperature sensor
1Place the cooling water temperature sensor in container of water and slowly heat the water