I have several mowers with small Briggs and Tecumseh engines and I have always used straight 30 HD oil in them. But I know that Briggs now recommends 5/30 synthetic oil as their first choice. I have in my stash a lot of 0/30 M1 , and am wondering if that would be ok to use in place of the 5/30 ? I have 5/0 in a syn blend, would that work? I suppose the worst that would happen is that it might use more oil than before, right? And that would be no big deal as I check and top off the oil in everything before every use.