Don’t let those frosty temperatures stop you from getting the job done. STIHL’s heated carburetor, with its temperature-dependent on/off control switch, prevents the carburetor from freezing in winter work.
Electric Heated Handles
The electric heated handle helps you keep a firm grip on your machine even in the depths of winter, making operation safer. Maintenance-free, non-wearing heating strips in the front and rear handles, can be engaged with a switch as required for warmer and dryer handles.
Jet Carrier Temperature with / without Carburetor Heating
The graph above shows the temperature curve at the jet carrier of a chain saw with carburetor heating (red line) and without carburetor heating (blue line) at an outside temperature of 0°C. Immediately after the engine starts (dashed line shows engine RPM), the temperature drops due to the intake of fresh air and the fuel vaporizing at an ambient temperature of 0°C. There is a risk of carburetor icing.
Without carburetor heating (blue line), the temperature remains below 0°C and even falls further when the throttle is opened (maximum engine RPM). The reason for this is that much more fuel is drawn into and vaporized in the venturi.
The carburetor heating (red line) begins to warm the carburetor shortly after starting so that the temperature rises quickly in spite of the cold fresh air. When the throttle is opened, the temperature dips briefly (full throttle -> more fuel vaporizes), but then rises steeply because the next generator delivers more power at full throttle.
After a long period of full throttle, the temperature falls again owing to the cooling effect of fuel vaporization, but it always remains well above freezing point so that there is no risk of icing.
The two temperature curves, with and without carburetor heating, merge after a period of operation because the engine reaches its normal operating temperature at which there is no longer any need for carburetor heating.