Can I prevent carburetter icing?
Yes, carburettor icing is caused by the combination of highly volatile fuel, high humidity and low ambient temperature. The extent of cooling, caused by the latent heat of the vaporised gasoline in the carburettor, can be as much as 20C, perhaps dropping below the dew point of the charge. If this happens, water will condense on the cooler carburettor surfaces, and will freeze if the temperature is low enough. The fuel volatility can not always be reduced to eliminate icing, so anti-icing additives are used. Two types of additive are added to gasoline to inhibit icing:- – surfactants that form a monomolecular layer over the metal parts that inhibits ice crystal formation. These are usually added at concentrations of 30-150 ppm. – cryoscopic additives that depress the freezing point of the condensed water so that it does not turn to ice. Alcohols ( methanol, ethanol, iso-propanol, etc. ) and glycols ( hexylene glycol, dipropylene glycol ) are used at concentrations of 0.03% – 1%. If you
