20:1 is way too much oil. I ran mine with 32:1 lawnboy ashless and it ran great with it. probably could have run 50:1 but with these dont go any less. the commercial gassers run 100:1 sometimes but homelite isnt going to last long. i went on towers website and it said 249.99 so who knows maybe the mail add is more expensive. I bought but never used some amsoil the lawnboy worked for my tests.