Things You'll Need
Piece of wood
The mower deck blades on an Ariens lawn mower must stay clean and sharp to properly cut through grass. These metal blades will dull rapidly if they hit anything harder than grass, like rocks or metal, that may be hiding in the lawn. If they hit these objects repeatedly, the cutting edges will dent and can even break. When this happens, you'll need to take the old blades off and install new blades onto the mower deck.
Move the Ariens lawn mower into position on a level area of ground. Turn the lawn mower off and wait for several minutes to allow the engine to cool down. Engage the parking brake if your Ariens has one. Take the key out of the ignition, if applicable.
Disconnect the black ignition wire from the end of the spark plug. Place the wire in an area so it won't accidentally touch the spark plug as you remove the blade. Raise up the mower deck to access the underside of the mower.
Place the piece of wood on the underside of the deck. Spin the cutting blade until it hits against the wood. Make sure the wood completely blocks the blade from spinning further.
Unscrew the hex nut at the center of the blade with the socket wrench. Slide the hex bolt and washer off and take the old blade away from the mower. Install the new mower blade onto the post. Fit the washer and hex nut on top of the blade. Tighten the hex nut with a socket wrench.