How to Test a Lawn Mower

Testing Mower Deck Level

• 1

  Check the tire pressure in each of the four tires with a tire gauge. If a tire is low, fill it using a tire pump. It's important that each tire have the same air pressure. Otherwise, it could cause your mower to look like it cuts uneven rows. Most push mowers use solid wheels and do not require a tire pressure check.

• 2

  Position your mower deck at the normal height you usually use to mow. Use the deck height adjustment lever located on the mower deck for this. Push mowers use individual deck height-adjustment levers mounted to each wheel. Check each wheel to ensure the lever is set to the same height.

• 3

  Cut a single row with the mower through the flattest part of your yard.

• 4

  Place the measuring stick at the right edge of the path you cut and take a reading. Reposition the measuring stick at the left edge and take a second reading. If the reading is more than 1/8-inch different, your mower deck is out of adjustment.

Testing Coil

• 5

  Remove the spark plug wire from the spark plug and position the blade of a Phillip's screwdriver inside the copper connector that you can see when looking into the spark-plug wire boot.

• 6

  Position the shank of the screwdriver approximately 1/8-inch away from the engine block. Do not touch any part of the screwdriver except for the plastic handle -- otherwise, you could receive a shock.

• 7

  Advise a helper to turn on the ignition, either by key or by pulling on the pull rope. Look for a spark between the engine block and screwdriver shank. If you see a spark, the ignition works properly. If you do not see a spark, move to the next step.

• 8

  Trace the spark-plug wire to the coil and then pull the wire off the coil. Press a new spark-plug wire onto the coil, and then place the screwdriver into the loose end of the spark-plug wire that usually goes onto the spark plug.

• 9

  Place the screwdriver within 1/8 inch of the block and turn on the ignition. If you see spark, the old spark-plug wire was defective. If you still see no spark, the coil no longer functions properly.