First make sure your EZ start battery is fully charged. Make sure the fuel cap is tightly closed. Check all the fuel and pressure lines to make sure they are secure. Remove the glow plug, reattach the wire and hold it against the side of the head while pressing the EZ start button. Does it light up? If it does, screw it back in and try again. Is fuel getting to the carb?
If it's cold there, warm it up inside, then take it out and try starting it again.
The factory settings on a 2.5 usually make it fire up quickly when it's new. Don't make any changes to the carb settings till it's broken in.
If you still have a problem getting it to fire, take it to the LHS to have it checked.