Honda BF50 (5HP) BF5A Outboard Motors Shop Manual., Page 32Get this manual
BFSOaBF5A bINSPECTION
THERMOMETER
THERMOSTAT
1) Inspect the thermostat visually for damage
2) Suspend the thermostat in heated water to check its operationDo not let the thermostat or thermometer touch the pan or false readings will result
121THERMOSTAT
heated to more than (12 )
3) Replace the thermostat if the valve stays open at room temperature, or if it responds at temperatures other than those specified
131 HEATER