I run seafoam in every tank. Its good stuff. I just add a shot when i fill up. I'm running a 2 stroke 40 Mariner, and I only use merc oil in it. My boat is run at least once a week, usually more. The gas doesn't sit around long, but I still like the "insurance" of adding the seafoam. I haven't heard one bad thing about it, and it can't hurt!
Sinker