In the following guide we mainly focus on walk-behind mowers since the majority of lawns are served perfectly well by these machines. However if you have a lawn that is larger than half an acre you may want a riding mower. If you have a yard that is between a quarter and half an acre consider a self-propelled model. This basically means you do less pushing. Self-propelled mowers are especially helpful on hills. Also pay special attention to blade size. Look for a mower with a blade thats at least 20-inches long if you have a larger yard. Conversely if you have many narrow areas to mow a smaller deck the area within which the blade spins around is best.
Some lawn mowers such as the Craftsman 37705 have a washout feature. It is essentially a garden hose fitting on top of the circular blade cover. This allows you to pump water into the blade assembly while running the engine. That action is designed to flush dirt and grass debris right out.
With the mower still on its side grab your socket wrench and wood block. Place the block inside the blade well. This is to prevent the blades from turning while you loosen their bolts. Remove the blade mounting bolt/bolts. A typical mower will have one blade like the Craftsman 37700 I serviced for this guide (one mounting bolt). Some like my Honda HRR216VKA have two blades an upper and a lower (two mounting bolts). Each blade should have at least two cutting edges.