For best results, the mower blade must be kept sharp. Always replace a dull, bent or damaged blade. To remove the blade, disconnect the spark plug wire from the spark plug and place the wire where it cannot come in contact with the plug. Turn the lawn mower on its side. Make sure the air filter and carburetor are up. Next, use a wood block between the blade and mower housing to prevent the blade from turning when removing the blade bolt. There are blade holder accessories available to assist you with this task.
You should always protect your hands with gloves and wrap the blade with heavy cloth. Now, remove the blade bolt by turning them counter-clockwise. Remove the blade.
To replace the blade, be sure the trailing edge of the blade, opposite the sharp edge is up toward the engine. Also, the star patterns on the blade and the mandrel must align before inserting the bolt. Be sure to use a block of wood between the blade and the lawn mower housing to prevent it from turning. Tighten the blade bolt clockwise. The recommended tightening torque is 36-44 foot pounds.
Blade bolts are specially heat treated, if the bolt needs replacing, replace only with an approved bolt.
Ottawa Mower Repair Facility