What's the correct gas oil ratio for this blower? I thought 50:1 but someone told me 40:1 is the correct ratio suggested by manufacturer. And what's the oil you use? must I use stihl brand 2cycle engine oil? how about lowe's pro-mix brand? By the way, what's the correct procedure to start it? 1-2 pull with choke on and then pull with choke off until it starts? do I need hold the throttle while pulling? And I don't see the primer button on this machine though. not required on this? any suggested maintenance I should follow? last question... what's the electrical plug like thing right above the choke switch?