Ref the FB 6 and FB 26 PN..page 14,para 25,highlighted,covers `Carburettor De-icing(Mk26 when fitted); each engine had a 9.5 gal tank and pump,to pump alcohol into the carb.in icing,or de-ice the carburettor,at 2-2,5 gph (lo) or 7.5gph on Hi setting...