It's a Troy-Bilt Brigs and Stratton 550 EX push mower. I just bought it last year, and it worked fine. It has been sitting in the garage with no use for about 4-5 months now. I just pulled it out, put gas in it, checked the oil and tried to start it. No go..the engine just rolls over, there's no sputter or anything. It just won't start. I'm really not good with this kind of stuff so I was wondering if anyone has any tips or advice.