37:1 mix? I am reading my manual and it says to go 64:1 for petroleum based and 80/100:1 for synthetic. That seems like way more oil than is necessary and they even say that it could damage the engine voiding the warranty. FWIW I am running Klotz in my new Brison 3.2 at 80:1. It runs great. I know this doesn't have anything to do with your question, but I do know that my Ryobi weed wacker runs terrible if I get too much oil in the fuel. I haven't run my Brison with too much oil so I don't know if it would have the same effect. That might be something to look at.