When a lawn tractor does not start, it can be a mildly confusing process to determine why. However, the most common reason for the tractor not starting is the battery. Whether the mower has been sitting for a short time or a long time, the first place to start is the battery. The process of checking the battery is simple, but it should be followed exclusively to ensure safety.
Locate the battery on the tractor. Some mowers place the battery under the seat. Others locate the battery under the hood by the motor. Check the owner's manual if the battery is not in either of these locations.
Clean the top of the battery with a rag, if necessary.
Read the top of the battery to determine its voltage. Most riding mowers use either a 6-volt or 12-volt battery. This information will either be on the top or side of the battery.
Set the multimeter to the 200-volt DC setting. Read the manual to ensure the proper setting is used. Some multimeters use symbols to designate the difference between A/C and D/C settings.
Place the red probe on the positive terminal of the battery and the black probe on the negative terminal. Read the voltage on the screen. If the voltage does not match, or in some cases exceed, the voltage of the battery, go to the next step. If the voltage is correct for the battery, check the connections and fuses on the mower.
Open the caps of the battery to check the water level. The caps can be removed with a flat-blade screwdriver. The water level should be to the top of the metal plates inside the battery. If the water level is low, fill the battery with distilled water and replace the caps. Some batteries do not have caps; they are sealed and cannot be checked. If the water level is correct or filled, place the battery on a charger to regain the proper voltage.