I have a 6.5 HP 4 cycle Toro lawn mower and a 4 cycle 10 HP generator, both B&S engines. I've been using Amsoil ASE 10W-30/SAE 30 in both the lawn mower and generator but am thinking since I sometimes use the generator in the winter (Chicago area) I would be better off running Amsoil AFF 0W-40 in the generator. What do you all think about this?