out of gas, timing off. bad plug, safety stop still on, bent or sheared keyway,
starving for fuel
dirty carb bowl or water in the carb
Blocked air filter, need spark plug replacement,
If a start cord pull mower won't start, it could be due to several reasons. Common issues include stale fuel, a dirty air filter, or a faulty spark plug. Additionally, the mower may have a clogged carburetor or the safety features may be engaged, preventing it from starting. Checking these components can help diagnose and resolve the issue.
make sure the gas valve is turned on and you put the air filter in right
did you check and make sure you have plenty of oil. or maybe your lawn mower just needs a break.
your electric motor(I assume) probably wont have enough torque, That is on a Riding type mower, not a push mower, it might work on a push mower as long as its not self prepelled, because your motor probably still wont have enough torque!
replace it
bad bearing
replace battery & starter solenoid.. possibly carb.
you should give enough space between you and the horse so that if the horse kicks you will not be in the way, and you wont get hurt
get a new one