pull the starter 2-3 times with choke, if it doesent start, put it half choke and then try again. If it still fails to start, then turn the choke completely off and give it another 2-3 pulls.
dont put the gas cap on too tight, you might be creating a vaccum, which keeps the gas from flowing into the carb, ultimately not getting any gas to the engine.
make sure you use some 28-30:1 break in mix, if you have some starter fluid put some in the plug hole and try again.