RE: Beware of O.S.
Every new engine I've bought (doesn't matter what brand), I take it apart and flush it out good and take a look around inside (just in case). All you need is a tiny little filing, thread, etc or whatever to go swimming around the inside of that brand new $500+ motor the first time you fire it up.....[:@]
That O.S. 120AX is worth what...$280? Ounce of prevention...pound of cure...and all that....
I never trust a 'factory' to 'get it right'. Humans are humans at the end of the day and will make mistakes.