My jerry cans for power equipment premium gasoline, and tractor reg diesel, all get the equivalent of 1 oz/US gal of Seafoam added when I fill them. It works very well as a cleaner, stabilizer and moisture controller. I know this because after 2 1/2 years sitting outside unprotected with a full tank of SF treated gas, my walk behind snow blower started first pull and ran smoothly. My newish green 22hp gas riding lawn mower's manual actually recommends storing it over winter with a full tank with SEA FOAM as a stabilizer. Works great! Pre SF days any gas equipment left with fuel for a season or 2 required a complete emptying and fresh gas or trouble 4 sure.
I bought an old 1981 50HP Mercury Thunderbolt outboard with boat 6 years ago and after a SF gas treatment it started WAY faster, idled WAY more smoothly, and the fuel was fine after a
winter's storage. My employee recommended I try it, and I was sold on it right away.
I add a can of SF to my 2006 Tacoma's gas tank every oil change. No exaggeration or kidding, the old pickup starts with barely a crank of the starter right after adding it, where before it always takes a second to fire up. This is consistent behavior after treating my pickup's gas with SF. Starts, idles, and runs noticeably better. And it's not from the oil change.
My 2017 B2650HSD has 660 hours and has always had 1/128 SF as stabilizer and treatment in the regular diesel. I have never had fuel issues in our sometimes brutal winter cold here in MB and she always starts with a little glow even if with the block heater NOT plugged in. The fuel has never gelled or grown anything in it.
Just in the saving on wasted fuel before SF days, when all the summer gas tools got drained of gas which was dumped, or it burned off sitting there idling until the tank and carb run dry, I can justify the expense of Seafoam maintenance treatment for all my fuels.