Lawn Tractor: Won't Start

The purpose of the battery is to provide power to the starter. This will allow the engine to turn over and ultimately run on its own. A dead or weak battery will not be strong enough to apply the appropriate amount of power required by the starter to create a spark. This can prevent your tractor from starting. To test the battery, first take a digital multi-meter and switch it to DC and 13V. Place the red lead on the positive terminal and the black lead on negative terminal. You will need to replace the battery if it reads below 10.5 volts on the multi-meter. To replace the battery, remove the battery cables, starting with the negative terminal, and remove any hold-down clamps. Then, you can re-install a new battery.

The job of a switch is to allow the flow of the electrical current that causes your tractor to start. A lawn tractor will have several different switches, and some exist for purely safety reasons. The first switch you will want to inspect is the seat safety switch, which shuts off the lawn tractor immediately in the case of a roll-over or other mishap. To check this switch, first locate it under the tractor’s seat. Take an ohmmeter, and attach both ends to the 2 ends of the switch. At this point, simply press down on the seat where the switch is located, and it should read a connection. If it does not read a connection, then the seat safety switch will need to be replaced. The next switch to check is the clutch safety switch. You can find it under the hood on the floor of the unit. Remove the wiring harness, lower the blade deck, and push the tabs on the switch in to remove it. Using your ohmmeter, attach the cables to the left side of the switch, the press the button up and down. You should see a reading go off and on, and if so, repeat the process for the right terminals. When you test the right terminal, you should have the same result as the left terminal, however, the readings for power on and off should be the opposite of the readings on left terminal. If they read the same at the same switch position, the switch is bad and needs to be replaced

The fuel filter is located between the fuel tank and the carburetor and eliminates debris from entering the carburetor and the engine, which can cause damage. You can remove the fuel filter by gently twisting the fuel line off both ends and blowing through it. There may be an arrow indicating the direction the fuel should be flowing in, so be careful to re-install in the correct direction. The fuel filter should be replaced yearly as a part of regular maintenance.

Your lawn tractor’s spark plug ignites the air/fuel mixture in the combustion chamber, which allows the engine to run. A faulty spark plug will make it impossible to start your tractor. To check the spark plug you will need to remove the wire from the plug by carefully twisting and pulling on the spark plug boot. Remove the spark plug and check its condition; a spark plug’s normal color should be light brown or grey. If the plug is dirty, you can attempt to clean it and re-gap to the manufacturer’s specifications. However, it is often better to replace the spark plug with a new one as a part of regular maintenance. You will also want to check the plug for any deposits, breakage, melting, and corrosion. If you see any of these symptoms, replace the plug and re-gap to the manufacturer’s specifications.

A solenoid is an electrical switch that uses a small current to control a higher current. A small current is used to energize a coil that will pull a magnetic switch into place and allow the flow of a high current. The solenoid will shut off the high current when necessary as well. There are both 3- and 4-pole solenoids, but most are 3-pole types. The only difference between 4-pole and 3-pole solenoids, is that the 4-pole type have a separate ground, whereas the 3-pole type grounds itself out when bolted down. To test your solenoid, first take 2 jumper wires and attach the alligator clips to the positive and negative terminals of the battery. Next, attach the negative wire to ground on the solenoid (clip onto the back of a 3-pole or the negative of the 4-pole), then attach a volt meter to both large terminals on the solenoid. Attach the positive jumper from the battery to the small connection on the solenoid. You should hear it click into place and the volt meter should read 12 volts if it is in good working condition. If you do not hear the switch click or see 12 volts, the solenoid will need to be replaced.

The purpose of the fuel lines is to deliver fuel from the fuel tank to the carburetor where it is mixed with air for combustion. A badly clogged or cracked fuel line can prevent fuel from reaching the engine and therefore can make your tractor hard to start. To check your fuel lines for a clog or crack, first pull the fuel line off the carburetor gentle in a twisting motion and do the same on the fuel tank and fuel filter. You can simply blow through the lines looking for anything unusual coming out such as thick, dirty fuel, or anything else unusual. If you cannot blow through the line at all, then you know that you have a blockage. In most cases a blockage can be cleaned to allow the lines to work properly again. Lines should be replaced if they look old and cracked, as they can leak and cause a fire.