The ignition system in a lawn tractor comprises the ignition switch, battery, spark plug or plugs, and the ignition module. The battery sends voltage to the spark plug to ignite the gas and air mixture in the carburetor to start the engine when you turn the ignition key. The ignition module converts the 12 volts from the battery and directs it to the spark plugs in the correct sequence in the event of a John Deere V-twin engine lawn tractor with two spark plugs. You must first ensure that your spark plug isn’t prior to assessing your ignition module faulty.
Park your John Deere lawn tractor on a flat surface, engage the parking brake, transfer the”Forward/Reverse” pedal to the middle”Neutral” position and turn the ignition key off. Permit the motor to cool.
Open the hood and remove the black rubber spark plug boot from the plug on the motor side near the bottom. Place a spark plug wrench on the plug, turn it counterclockwise and remove it.
Clean the spark plug with a wire brush to remove any carbon residue and replace it in the cylinder. Replace it, if the porcelain is cracked on the plug.
Insert a metal feeler gauge to the plug top between the metallic plate beneath it and the wire on top. Insert the part of the feeler gauge marked 0.76 mm or 0.030 inches. Press on the wire down to get the feeler gauge, then eliminate the gauge.
Connect the spark plug boot to some tester. Connect the tester lead wire. Depending upon the version of tester, the wire could be shaped as an alligator clip or as a spark plug boot to fasten to the top of the plug. Turn the adjustment screw on the spark tester to 4.2 mm or 0.166 inches.
Turn the ignition key to the”Run” position and observe the clear window in the spark plug . The ignition module is acting, if there’s a powerful blue light in the window. Replace the ignition module with a fresh one, if there’s a intermittent lighting.