I have a weed eater brand push mower and it bogs down and blows out black smoke as well as vibrates real bad its only 2 months old I was told that putting mid grade gas in it would do this? What should I do

Take this mower back to where you bought it as no mower that new should do this - black smoke and vibrate. Did you put in the proper lawnmower oil that came with the machine and not car oil? Regular gas works just fine in a mower. You don't want to put a higher octane gas in a mower though. Did you use fresh gasoline in the mower?