The level of hydrocarbon (HC) emissions, from a spark-ignition engine using a 30% iso-butanol-gasoline blend was experimentally investigated. Experiments were conducted on a Hydra single-cylinder, spark-ignition, fuel-injection engine. HC emissions were measured as a function of fuel / air equivalence ratio, ignition timing and engine speed. The effect of varying the temperature of cooling water on HC emissions was also investigated under three fuel / air equivalence ratios (lean, stoichiometric, and rich). Results shaw that retarding ignition timing with respect to maximum break torque (MBT) has a great effect on HC emissions reduction, where for lean mixture, Phi = 0.85, retarding ignition timing by 6 degrees from MBT reduces the exhaust HC emissions by 12%. The level of HC emissions is also reduced by 30% at MET, as the cooling water temperature increase from 55 to 90 degrees C. It is noticed that as the engine speed increases, the level of HC emissions decrease.