Try pulling out the spark plug and clearing the cylinder
get a new one
replace it
There could be many reasons why your Sears riding lawn mower won' shut off. The key could be jammed for example.
because it needs a 1600 vee dub engine in it to make it go faster to have lawn mower races
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!
not getting gas. clean\carb rebulid needed
put some gas into it and some oil and pull the cord put some gas into it and some oil and pull the cord
Perhaps it is the starter drive. That happened to my riding mower. Got the drive replaced, works fine.
Your flywheel key might be sheared
There are way too many reasons for a mower not to run. Without more information it is impossible to diagnose the problem. If you still want help try asking again with the make of mower, the engine, details of what you have done and what the symptoms are.
did you check and make sure you have plenty of oil. or maybe your lawn mower just needs a break.
The fuel filter is clogged or the carburetor needs to be cleaned and/or adjusted.