I've run Pennzoil Platinum 10W30 in my Honda mower with the GCV160 engine after a few Pennzoil conventional 30W flushes since it was new. I change it each year, but it's hardly dirty even after a year of use.
I also run Pennzoil Platinum 10W30 in my Generac Ultra Source 15KW 4582-2 portable. It has a 992cc dual-cylinder air-cooled engine with gerotor oil pump and spin-on filter. No issues at all.