Why won't my 33cc engine start?

Check your basics first, ignition, compression and fuel.

See if your spark plug is firing, could be worn or simply need cleaning.

Check compression, should run on anything over 100lbs.

Makesure fuel is being delivered to combustion chamber. Also ensure that your fuel is fresh and not contaminated with water or trash. Oftentimes, contaminated fuel will be apparent due to a flooding condition.