I saw an off topic thread talking about gasoline octane affecting car performance. I've heard the argument about running high & low octane fuel many times, in fact my ex-father in law who is an auto mechanic swore the min. 87 rating was all anyone ever needed to run. I've also heard plenty of people swear by 93. But.......my question is how about these extremely hard working mower engines? I personally put only 93 in my mowers & all hand held equip. They're like race cars so I try to treat them that way even though I've been told it's a waste of money. What's your opinion? I've been reading loads of pages in this forum & respect everything you say. Glad you're here.