I've got a couple small garden tractors that I'm working on for a winter project. Been years since one ran, so going to try the Seafoam. Most of my older single cylinder tractors, I've used MMO for years, since no lead came out. Found that out, from the guy that rebuilt the head on the 223 cu. in. Ford 6 popper in my then, '64 1 ton Ford. Way cheaper than the stellite valve seats.
On the matter of water in the engine. How many remember John Deere had water injection of the old Model D's, to prevent pinging on distilate, or kerosene..?? I have some friends that had an old D with that on. Guess the old girl really got with the program, when they turned the water on.