Battery cables loose or corroded which is not likely with a new battery but check the ground connection and the connection at the starter. Charge the battery with a battery charger and then start the mower. Disconnect the positive battery terminal and if the engine dies the problem is with the charging system. Check all the wiring coming from the alternator located under the flywheel. If nothing is wrong then you will have to remove the flywheel and find out what is defective. Can be a diode has failed or the alternator is defective.
I usually do over night.
If it is still in the tractor hooked up unhook it and try charging it if it still won't charge the battery is probably bad. If it does charge out of the tractor you might have a short in your wiring on the tractor. Hope this helps.
I assume you mean a car battery. Yes, you can jump your lawn tractor with a car battery, following the usual precautions for jumping any vehicle.
weak battery?
Usually 6v, can be 12v.
If both batteries are of the same voltage (12 or 6) yes, you can use the charger. make sure that they are of the same voltage.
Yes,its attached to red wire on battery
It uses a 12 volt lawn mower engine battery.
Yes, a lawn tractor can be jump started with a car battery, in the same manner as another car can be jump started.
Try checking the pick up coil or the magnets on inside of the flywheel.
Most take a 6 volt battery.
Battery is 12 volt, U1 group