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How to Troubleshoot a John Deere L100

By Truell Bliss ; Updated September 21, 2017
Attend to your lawns with a John Deere L100.

Regular use of a John Deere L100 lawn tractor will help you to maintain the health of your lawn and provide curb appeal for your property. The model L100 easily handles mowing tasks on level lawns and elevations with gradual slopes. If you keep your lawn tractor well maintained, you can minimize the number of times that mechanical or engine trouble may occur. You should take immediate action to troubleshoot the most common causes of “down time” your John Deere L100 experiences.

Engine Will Not Start

Lift up the driver’s seat and check the gas tank for fuel. Add fuel if necessary.

Check the spark plug and wire. Use a spark plug wrench to “snug up” the plug. Ensure the wire makes good contact with the spark plug. Mowing creates vibrations that may loosen connections.

Disengage the power take off (PTO) lever. The lawn tractor will not start with the PTO lever in the “Up” position. Move it to the “Down” position prior to starting.

Depress the brake pedal when starting the engine. The engine will not turn over unless the brake pedal is depressed while your turn the ignition key.

Check the fuel filter for visible particles of dust and dirt. To clean the filter, undo the gas lines with your fingers and remove the filter with a socket wrench. Pop the top off the filter and flush out any sediment with gasoline.


Check for corrosion on battery terminals. If the terminals show signs of corrosion, remove the battery from the tractor and clean the terminals with a battery terminal brush.

Attach a battery test gauge to the battery. This tool will tell you if the battery needs charging.

Lift the hood of the tractor and check to see if the fuse has burned out. If so, replace it with a new 20-amp fuse.

Check the engine starting procedure. Disengage the PTO lever and depress the brake pedal prior to turning on the ignition.

Check headlights for loose or burned out bulbs. Tighten loose lights and replace lights when they burn out.


Unlock the parking brake and engage the “freewheeling” lever, located between the two rear wheels, to allow the tractor to move while the engine runs. Push the lever in, toward the steering wheel, to engage it.

Check for dirt or accumulated grass on the tractor’s drive sheaves. Use your hands to remove all materials that interfere with belt operations. If the tractor begins to vibrate or rattle excessively, stop mowing. Check for debris interfering with the belts and check for a bent or broken mowing blade.

Examine the drive and attachment belts. Replace any belt that shows wear.


Adjust the speed of your mower if you notice patches of uncut grass. Mow at a slower speed for a thorough cut. Check for debris accumulation under the mower deck if uncut patches continue.

Check the level of the mower deck if the blades cut unevenly. Uneven cutting can occur when you have unequal pressure in your tires or when you have a dull, chipped or broken mowing blade.

Raise the height of your blades if the grass shows signs of “scalping.” Scalping may also occur when you turn at too great a speed or when you mow over uneven ground. Low tire pressure also causes scalping.

Clean out the discharge chute frequently. Mowing wet grass causes the cut grass to build up and plug the mower’s discharge chute. This also occurs when you cut very tall grass or when you operate your mower at high speeds.


Things You Will Need

  • Fuel
  • Spark plug wrench
  • Socket wrench
  • Battery terminal brush
  • Battery test gauge
  • 20-amp fuse

About the Author


Truell Bliss retired from the restaurant and hospitality industry after almost a lifetime of service. An officer in the American Culinary Federation, he earned his dietary manager certification and progressed into positions as chef instructor, chef manager, dining services operations manager and finally, director of food service.