I am a believer at least for small engines. I had a chainsaw and a weedwacker that were so hard to start that you would have to stop and rest your arm. A landscaper convinced me to try Seafoam. I had low confidence in any type of "mechanic in a can" But Wow, both of these start with one or two pulls like they are supposed to. I have been keeping a couple cans on the shelf for years since then.
I bought a new Simplicity snow blower a number of years ago. The tech was also the delivery guy. He talked about the warranty and said fuel issues were not covered. Briggs had some stabilizer they sell, he talked about Stabil but said he had seen plenty of issues with that...then he looked at me and smiled and said...just use Seafoam. Have been ever since....zero issues. All my small engine stuff starts right up after sitting for months at a time.
