The carburetter Heater is intended to add a small amount of heat to the carburetter body in order to keep the temperature of the body above freezing point, so that any ice formed will not adhere to the carburetter throat. Because there is no significant heating of the actual intake air, there will be a negligible loss of full engine power when the carburetter heater is switched on, therefore the carburetter heater can be left switched on all the time if desired without detrimental affect on the engine performance.