Step 2- Remove the spark plug using a spark plug socket. Hold the end of the spark plug wire close to a metal surface. Look up online to see if you have the correct spark plugs for this engine. What causes clogging in fuel injectors or/ and their accompanying filter baskets is the presence of carbon, old fuel, and residue. Once you get the socket over the spark plug, place your hand over the head of the wrench, grasping the head firmly and pull the handle, hitting it gently with the palm of your hand to get it going. How to Tell When it Is Time to Change the Spark Plug in a Lawnmower. Test the spark plug ignition by disconnecting the spark plug wire from the spark plug. A fouled or bad spark plug is a plug that has become covered with a substance like oil, fuel or carbon or one that is blistered from running too hot. You should see a spark. And so, it can tell the onboard computer as well as ignition system about electric pulse transferring that fires spark plug. The spark plug is an essential component of any gasoline-powered trimmer or edger. The easiest way to test for spark is to pull the spark plug boot off of the number 3 cylinder spark plug and install a spark tester. However, a misfire may also be a symptom of other faulty components—anything from a bad spark plug to an engine mechanical problem can cause your vehicle to experience misfires. Spark plug wires are responsible for transmitting the electrical current from a vehicle's electrical system to the engine spark plugs, where the electrical current is used to ignite the engine air/fuel mixture. Spark plug gapping: To prevent a reoccurrence, use the right spark plug size. 4. When there is fuel and air in your cylinder and the spark plug doesn’t ignite it, it gets pushed out of the cylinder on the compression stroke and as soon as it … A bad spark plug can cause engine misfiring which can also set on the engine light. A single spark plug will usually cost in the range of $4 to $10 depending on the type of spark plug material.But, since the amount of plugs you need is dependent on how many cylinders your vehicle has, you will need to multiple that figure by 4, 6, 8, or even 10 in some cases. How can I tell that my CDI is bad? ; Step 3- Inspect the spark plug for very stubborn deposits, or for cracked porcelain or electrodes that have been burned away.If any of these conditions exists, replace the spark plug. The spark plug provides an ignition source for a small engine, such as the kind that powers a lawnmower. Keep in mind that a misfire can damage the catalytic converter, so you should address the issue immediately. Most auto parts stores have them for a few bucks. Attach the spark tester to the distributor end of the coil wire. By Alex Palmeri. Coil Pack Problems Usually, if a coil pack is bad, there will be a loss of fire or spark in one or more cylinders. Mowing becomes problematic when the spark plug is bad. One possibility you may overlook is having bad or worn spark plugs. Else if the sparks are yellow or there is no spark at all then the spark plug is bad. For most vehicles, it is recommended to replace the spark plug every 30,000 to 50,000 miles . If your spark plugs become dirty or fouled, it can affect how your engine runs. Spark … Engine hesitation can possibly mean your spark plug is bad. The engine shows poor performance and keeps stopping while mowing. Keep it plugged into the spark plug cable. It is also possible that faulty spark plugs are causing your battery to drain. April 9, 2018. Use a spark plug wrench with an extender. Results. Second, if your plugs indicate a problem related to the plug’s heat range or the plug is simply worn out, you can fix these problems with a new, and correct, set of plugs. One possibility you may overlook is having problems and needs a change or there is no at... 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