Self propelled mowers are not self driven. The mower has a safety switch which does not allow the unit to turn on itself. A person is required to turn on and steer the mower.
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!
check your coil out
starving for fuel
replace it
bad bearing
get a new one
there is what they call a key that locks the wheel and axle together must had stuck on the old wheel
because it needs a 1600 vee dub engine in it to make it go faster to have lawn mower races
dirty carb bowl or water in the carb
I would love to help you out here but I have no idea what you are saying? Do you mean the drive wheels wont move your "self propelled" mower?? if so you can start by checking the belt drive, belt may be worn loose or missing. Also the drive wheels have gears molded into the inside centers of them, if these plastic gear teeth wear out the wheels wont engage and mower will not move without manually pushing it. Lastly the gear box may be dry of gear oil or defunct and will need to be replaced or filled, by means of a small rubber or plastic plug on the top of the gear box. Or by starter whines and wont turn the "WHEEL".....do you mean wont turn the flywheel???? If so be certain the battery is charged fully allowing total starter power to spin over the engine. If battery is good and connections are good and engine is not seized....replace the starter.
Try pulling out the spark plug and clearing the cylinder
Perhaps it is the starter drive. That happened to my riding mower. Got the drive replaced, works fine.