I often simply spray it into the spark plug holes and let it sit for a while. And I do this with a warm engine, and turn the engine over by hand via the fly wheel. It might not, and likely will not cure a clogged carb jet, which you most likely have. It will clean all the carbon off of your spark plugs, pistons, and liners, which will make for a better running engine. I really hate to say that something is a engine tuner in a can, because almost nothing is. But seafoam does work, and doesn't harm anything.