I've just received a free Lawn-Boy push mower from someone that has recently moved away and I can not get it to start. It is a Self-Propelled Lawn-Boy(L21ZSM) Model # 68054. In the condition that it appears to be in, I do believe that it was poorly maintained and left out for sometime. I have (minus the installation of a new spark-plug) partially taken it apart and checked the obvious. So please, any further suggestions before taking it apart?