Lawn Mowers

Published on August 1st, 2017 | by Kyle E


How to Replace the Spark Plug for a Husqvarna R120S

The following instructions are for the Husqvarna Rider, which is for the model number R120S. Before attempting to work on/with your equipment in any way, always refer to your owner’s manual for safety information.

  1. Remove the ignition cable boot and clean around the spark plug.
  2. Remove the spark plug wit ha 5/8″ (16 mm) spark plug socket wrench.
  3. Check the spark plug. Replace the spark plug if the electrodes are burned or if the insulation is cracked or damaged. Clean the spark plug with a steel brush if it is to be reused.
  4. Measure the electrode gap with a gapping tool. The gap should be 0.75 mm/0.030″. Adjust as necessary by bending the side electrode.
  5. Reinsert the spark plug, turning by hand to avoid damaging the threads.
  6. Important: Inadequately tightened spark plugs can cause overheating and damage the engine. Tightening the spark plug too much can damage the threads in the cylinder head.
  7. Tighten the spark plug, once it touches the seating, with the spark plug socket wrench. Tighten the spark plug so that the washer is compressed. A used spark plug should be turned 1/8 of a turn from the seated position. A new spark plug should be turned a 1/4 turn from the seated position.
  8. Replace the ignition cable shoe.

For information about safety, warranty, and your specific model, read and be familiar with your owner’s manual.

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