Fuel in the chain lube tank doesn't really matter.But oil in the fuel tank does.However don't worry you haven't caused any harm to the motor.Remove the fuel pipe to the carb,flush out,and refit. Simply drain both tanks,and replenish with correct fuel/chain oil.May take little starting as it will be pulling chain lube in.Probably have to remove and clean the spark plug a couple of times as it will be oiled up.Once its pulled the fuel through it will start.Manual if needed.www.stihlusa.com/stihl_ownersmanual...
paul, January 2012