I am trying to identify my chainsaw. I have had it for ever but seem to have forgotten what type oil is used because it appears that the reservoir for what I thought was the bar oil actually seems to provide the oil for the gas?? So what type of oil do I use?? I bought this used back in the 80’s and used it quite a lot. Then put it away and now I want to use it but seem to have forgotten what type oil goes in there I would like to get a owners manual if possible but I need to know what I have first