If your leaf blower has fuel but fails to start, either the ignition coil, the spark plug lead, or the spark plug is faulty. The magneto on your leaf blower delivers a pulse of low voltage electricity to the ignition coil. The ignition coil itself is a step-up transformer containing a primary and secondary coil. These coils boost magneto voltage high enough to ignite the fuel/air mixture in the cylinder by jumping the gap between the spark plug electrodes. Use an ignition tester to test the spark plug, the plug lead, and the ignition coil.
Remove the spark plug lead by pulling the rubber boot off the plug.
Clamp the alligator clip on the ignition tester to the spark plug and insert the other end of the tester into the connector inside the rubber boot.
Pull the starter rope, but stay clear of the ignition tester leads to avoid a shock.
Pay close attention to the transparent window of the ignition tester while pulling the starter rope. If you see a bright blue spark jump across the terminals in the tester window and the engine starts, both the ignition coil and spark plug are in working order. If not, go to the next step.
Remove the alligator clip from the spark plug and clamp it onto a bolt on the leaf blower’s cylinder head. Pull the starter rope; if you see a bright blue spark jump across the tester window, the spark plug is defective and must be replaced. If there is still no spark, either the coil itself has burned out, or the plug lead is defective.
Replace the plug lead and retest. If you do not see a spark jump the gap, the coil is defective and must be replaced.
Things You Will Need
- Ignition tester
- Spark plug lead (if required)
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