Sea Foam is a decarbonizer and works fine to clean carbon from combustion surfaces and rings. It only works in a running engine, not cold at all. It's been used for cleaning carbon from outboard motors for many years. There is also Deep Creep, the same product in an aerosol form. The major outboard mfgrs have sold their own equivalent products for many years also and they smell just like Sea Foam. I used it on an outboard motor I bought years ago and it smoked like crazy for about ten minutes (carbon getting blown out)! If you're inclined to use it, put the whole can in a gallon of oil/gas mix. Unlikely to hurt anything, but also unlikely to be needed in our high revving engines that spend most of their time at 50% or higher throttle settings. BTW, Sea Foam doesn't do squat to clean carbs.