My new(to me) 7900 just got here and I've got a few questions. I bought it off fleabay and it didn't come with an owners manual. Date code is 0508 which I assume is a 2008 saw although the previous owner said he bought it in 2007. it has the pre cat muffler on it. I read the owners manual(2010) off the dolmar site which says to mix at 50 to 1 due to epa regulations. Did dolmar recommend 50 to 1 pre epa? Is 50 to 1 normal in a pro saw with stihl or husqvarna oil?