How to Test a Yard Machine 664471 Lawn Mower

Make sure there is enough fuel in your Yard Machine 664471 lawn mower. You may have simply neglected to refill the tank with gasoline.

Start the engine after checking for fuel. If the engine cranks but does not start, remove the keys from the ignition and open the plastic cover over the mower's engine.

Replace the spark plug if you have had the machine for some time. Disconnect the single, black cable connected to the plug, and then insert the wire into a new spark plug. This will likely fix the engine's starting woes.

Remove the Yard Machine 664471 lawn mower's engine cover again and check the air gap. This air gap is the space located between the magnetic coil and the flywheel. Follow the spark plug's cable back into the engine assembly. It comes to rest beside the circular magnetic coil, and just behind the coil is the flywheel. Measure the air gap's width. It must be a precise width between 0.010 and 0.015 of an inch.

Loosen the Yard Machine 664471 lawn mower's magnetic coil with your wrench and reposition the coil incrementally closer or farther away to the flywheel in order to ensure the air gap falls between the 0.010 and 0.015 of an inch measurement. Remeasure the air gap when finished to confirm it is correct.

Replace the engine cover. The Yard Machine 664471 lawn mower should be restored to normal operation.