I'm not a big fan of most Stihl equipment, but man I love the power and lower noise of these machines, but this is the second time the same blower has blown (excuse the pun) up. It's probably just another valve, but I don't have the expertise to fix them when they go. I guess I should learn how to replace valves if I'm going to keep using these things. I run Stihl oil at 50:1 with mid-grade fuel. Maybe I should run the ever-expenisve premium, although I don't know whether two more octane numbers (I have no idea how they rate fuel) will make a huge difference. Do the 4-mix trimmers eat valves the same way?