ORIGINAL: cloudancer03
I bought sthil ultra ..I understand pezoil is good and though I know nothing about it another name dropped is a product called royal purple.I do know that most experts will tell you to stay away from amsoil!I enjoy working with valleyview and they are big fans of sthil..this also my first gasser but certainly not my last.I am getting advice to use 89 octane as it has a little less etnanol.
Istrongly recommend steering clear of the Royal Purple also, it's only certified by the NMMA for water cooled engines, no certification from API or JASO for use in air cooled engines. If you do some digging you can find reports of the stuff causing catastrophic failures in hard working air cooled engines.