Things You'll Need
When your lawn tractor won't start and it just clicks when you turn the key or does nothing at all, you can assume there is a problem with the battery. A lawn tractor battery usually goes dead after sitting for a long period of time, but it can become dead after just a short time too. You can test the lawn tractor battery in several safe ways to find out if it is good and can be charged.
Locate the battery on your lawn tractor. They are usually under the seat of the lawn tractor or behind the engine under the hood.
Scratch off any debris or corrosion on the top of the battery with the flathead screwdriver.
Locate what type of battery it is. Next to the battery brand name is the battery voltage. Most lawn tractor batteries are 6-volt, but some are 12-volt batteries.
Turn on the multimeter to the 6V or 12V setting on the dial. Touch the red probe from the multimeter to the positive post on the battery. Touch the black probe from the multimeter to the negative post on the battery. It should read just a few decimal places below 6V or 12V. If the voltage is correct, move onto the next step. If not, then the battery needs to be charged with the proper 6V or 12V battery charger.
Unscrew the battery cables with the pliers and scrape away any corrosion on the battery posts with the screwdriver. Tighten the cables back onto the battery when done.
Pry off the battery cell top from the top of the battery with the flathead screwdriver. Look in the cells to make sure there is water up to the top of each metal plate inside the battery cell. A battery will not hold its charge without enough water. Fill each cell to the metal plate with distilled water.
Locate the fuse mounted next to the battery. Pull the fuse out and replace the fuse, since fuses cost only a few cents. Fuses can burn up easily and be the cause of your mower not starting.