My Mantis is 2004, and last few years has been a nightmare--and continues f or 2015. I never really bought the "new gas" scenario, but after trying th is last weekend and having it barely run--I did the new gas Monday AM (used regular, though). Got it started and it ran like a dynamo for about 20 min
--so now I am a believer in new gas! Shut it off for few minutes of raking, and then could not get it started. Rest of week same scenario, mess with C arb, changed filter, checked spark arrest screen, checked plug, used carb c leaner on "L" jet(rebuilt carb last year)--run's fine for 5-10 min--and the n quits. Talked to Mantis twice this week--little help, except comments on bad gas these day. Am ready to burn it in town square in Cary, NC.