you have a small engine on these models, with Two (2) spring tensioned screws, one being the idle mixture screw(This is air to fuel mixture) The second one is (fuel mixture to engine) Adjust both screws all the way in, then 1 turn anti clockwise or (open) continue with this in 1/2 turns out until you have your motor running just the way you would like.
Regard's Tony.
Anthony Cummins
March 2006
Under the back cover there should be a foam air filter.
Check to see that it isn't plugged up with oil.