tlandis7, Ensure battery is good and fully charged, connections are clean and tight.
Engine cranks(turns) OK but does not start(fire). Remove spark plug and with new plug attached to spark plug wire ground plug to engine and observe for spark between plug gap. If spark is observed OK reinstall with properly gapped plug and try starting again. If no spark there is something wrong in the ignition system. Coil could be faulty, fly wheel key may have sheared(throwing timing way off), ignition module or wire/connector may be bad.
Have good spark engine does not start. remove air filter and pour approx. 1/2 oz. of fresh fuel in carburetor and then try to start. If engine starts and runs until added fuel burnt and quits, it will be a fuel related issue. Ensure you have fresh uncontaminated fuel in tank. Remove gas cap momentarily and see if fuel will flow(try to start), vent in gas cap could be plugged not allowing fuel to flow. Remove fuel line from carburetor and direct line into a container to see if fuel is flowing from the tank or if equipped with pump when engine cranked fuel should flow.
If no fuel, check fuel line pinched/plugged, tank shut off either not on or plugged, filter plugged or installed back wards(if directional), check for fuel tank internal screen plugged or if equipped with pump it may be faulty(check all lines on pump are not plugged and hooked in proper positions securely).
If fuel flowing the carb. float may be stuck in the closed position or if carburetor equipped with a electric shut off/solenoid it could be faulty/stuck/bad connection. Now if you are getting fuel to carb. and the bowl is filling, either the jets are clogged or you have not adjusted the screws out to the proper settings to allow fuel to flow, may need to clean and rebuild carb.. See the trouble shooting link/guide below for more info. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.