Nit answering ur post, but I also have a Generac (2 cyl LP 16kw) and have been using PYB 5-30 mostly. Mine just ran 15hrs on Thanksgiving!!!
Question for me is, are you doing yearly change? I am. Using auto filter? I am. Do you expect a difference in a synthetic over a conventional SN oil?
I'm just asking because I'd love to hear from another owner what their thoughts are. I've had mine since late 09 and I'm only at like 250hours. My fill home allows me to see a whole valve, it it SPOTLESSS and looks factory new.
I appreciate anything you share.