Use it in every gas and diesel engine, but only in the fuel, never in the oil. Not because I don't think it will be good for the engine, just that I forget to put it in at oil changes. Great results during the season, great for storage stabilization.
I use it in everything I own that has a carburetor. My float used to stick every so often on my 97 heritage. Within a few minutes of adding seafoam it stopped. Never stuck again as long as I added it a few times a month. Works great in the weed whacker too lol