Lawn mower won't start?

i have a 1 yr old lawnmower (Yard Machines ) & i went to start it this yr & it wouldnt start so i replaced the spark plug & still didnt start the spark plug had gas on it & when i was trying to start it gas was spiting out from some sliver thing with holes on it on the side i left the gas & oil in it over the winter( didnt know i was suppose to drain it) & i use straight gas in it can anyone tell me whats the problem & if i need a new 1 what is a good 1 to look at also if i screwed it up tell me what to do different next time thx....