Have someone remove the spark plug and ground the threads on the motor. Spin the starter motor to see of there is any flame between the spark plug electrodes. If there is no spark, replace the ignition coil with .011 clearance between the flywheel.
perhaps there is fuel shut off valve that is turned off...
check for compression. When you say "spinning over really fast", do you mean faster than it used to? If so, it could be valve sticking or needing adjustment, or a blown head gasket.
Changed the spark plugs lately? Air filter clean? Fuel in the tank?
Is there a choke that needs to be on when you first start it?
Grab the recoil (starter) cord and pull slowly. Do you have compression? If the engine is cranking too fast, maybe the sparkplug has worked its way lose.
This can be caused by a number of things. Maybe a clogged fuel line?
ID RUN A COMPRESSION TEST AND COMPARE THAT RESULT TO SPEC. YOU CAN HAVE FAILED RINGS OR BAD VALVES.
