Toro 724 snowblower won't start

One of two things will cause this. Either your piston rings have fried and your piston is stuck. The bearing on the flywheel is bad. Or actually one of thing, the crank shaft has broken. You willl need to take the motor apart all the way and see what is going on. If you take the flywheel off try to turn it by hand and see if you can turn it that wy. You also can try easier to check for first symptom is to make sure you are not in vapor lock. Remove the spark plug, turn unit upside down and see if you can get the motor to turn, if you can then replace the spark plug and it will start up. You can getvapor lock by running it low on fuel or the wrong fuel or running it to rich