Also this is a good point, don't forget to replace the fuel with something fresh and hasn't caramelized. Gas does weird things after it sits for awhile. You may even have some gummed up the fuel lines.If it sat for a year the gas could have been bad due to phase separation(a layer of low octane gas, and another layer of a mix of water and alcohol). Would run ok for awhile, but once you get to the water layer it would die and never start again until you replace the fuel.
Source: Had to clean out and unplug the gas lines in my old snowmobile once after I forgot to add stabil, it had been sitting for 10 months.