Kenmac is giving you good advice. In case you don't fully understand what he is saying:
Make sure the muffler isn't plugged with mud, nesting material, a potatoe or whatever. Have someone turn over the engine and hold your hand over it to see if the engine has compression.
Take a wrench and crack open the line at each injector just lightly to see if fuel is getting to them when you turn it over. (This can spray fuel out around the line / nut - wear eye protection). If a good spray isn't coming out, you have air in your lines. When you have steady fuel with no bubbles, tighten up the nuts again and try again. This is an easy and effective way to bleed air from your fuel system. (I know, it can also be environmentally irresponsible and can make a mess, but it's my preferred tactic).
Other possibilities if you change out your old fuel lines:
Pull the valve cover off and insure none of the valves are stuck open. Although two years isn't excessive, it can happen.
Not familiar with your model, but just in case you have a solenoid shutdown, make sure it opens when you turn the key on.
Make sure the throttle is set properly for start and that the linkage is working to the fuel pump.