I borrowed my Dad's Troy-Bilt Tuffy tiller to break up the garden and a new area to plant some grass. He told me my brother had borrowed it and had to run it with choke partially on to keep her going under load. I know it has never had any real carb work and my dad does not use any additives so I gave it a pretty strong dose of Seafoam and ran it for about 3 hours total. I will say this, the last hour after the first tank ran through she was running a lot smoother, I was impressed. When I dropped it off my dad fired it up and it needed virtually no time running with the choke open before we could take off with it, he said it was running better after start up and wanted to know what I havd did to her. I picked some up becasue I saw a huge wall of it at a small engine repair shop down the road from my work. My first experience was pretty positive.