2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 60Get this manual
Power unit NOTE: To remove the manual starter or flywheel magnet cover, see "Removing the timing belt and sprocket" (5-30)3Remove the thermostat cover and thermostat 2Water temperature 5862 (136144 F) Valve opening 0.05 mm (0.0020 in) (valve begins to open) more than 3.0 mm (0.12 in)
S6AG3120
CAUTION:
Do not reuse the gasket 3, always replace it with new oneNOTE: It is recommended to check the thermostat cover anode before installing the thermostat cover4Suspend the thermostat in container of water5Place thermometer in the water and slowly heat the water