Carb cleaner dissolves the varnish, gum and carbon deposits that build up in carburettors, throttle bodies, air intakes and idle control systems.

Symptoms of a dirty throttle body or carburettor are familiar: rough or hunting idle, hesitation off the line, stalling when coming to a stop and poor cold starting. On fuel-injected engines the throttle body and idle air passages collect an oily carbon film from crankcase ventilation, and cleaning it often restores idle quality without any parts being replaced.

Use it with care. The solvent attacks many plastics, rubber and painted surfaces, and on some engines the throttle body has a coating that must not be scrubbed. Work in ventilated space, keep it away from ignition sources, and be aware the engine may need to relearn its idle after cleaning.