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How to tune up your lawn mower (just in time for summer)

From cleaning to changing its oil to sharpening its blades, here’s how to prep your mower for summer.

Chris Monroe/CNET

Lawn mowers are tough. Like any machine, though, they need regular maintenance to run their best. Worse, neglect can cause a mower to fail completely. So before the summer mowing season really kicks into high gear, prep your mower right. From cleaning it to changing the oil to sharpening and balancing its blades, this guide lays out steps to get your mower -- and your garden -- in tip-top shape.

First gather all the tools and items you need.

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Step 1: Gather what you need

First gather your tools and equipment. You'll need a power drill, eye protection, work gloves and a blade sharpening kit. The kit should come with a ceramic blade sharpener and balancer. Expect to pay about $8 for the kit at your local hardware store. You'll also need a torque wrench (or a socket wrench in a pinch) and a wooden block. Consider having a rubber mallet on hand too.

Other items and supplies include a plastic drip tray, motor oil and a container for waste oil. Often a large piece of cardboard is useful as well an old rag or cloth.  Also know that this guide deals with push or self-propelled mowers, not riding mowers. While some advice here applies, they are another animal altogether.

Clear dirt, debris and old grass clippings from the blade area.

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Step 2: Clean it

To clean it, first start with a cool engine. If your mower has a fuel valve, switch it off. If you can, disconnect the spark plug, too. Next use a leaf blower to blast away any old dirt and major debris. Now gently lay the mower on its side, fuel cap facing up. Try to get rid of any junk on the mower's underside as well.

You might get away with using a garden hose to clean your lawnmower. The safest way, with the least risk of damage, is cleaning by hand.

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I know that many people prefer to hose their mowers down with a garden hose. I admit, I've done it. Still, doing that is risky. If water gets into the wiring, air filter or engine, you could really do some damage. Hand washing with damp rag is a drag, but also your safest bet.

Some lawn mowers, such as the Craftsman 37705, have a "washout" feature. It's 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.

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Step 3: Sharpen and balance its blades

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.

To sharpen them, secure in a table vise. Now attach the blade sharpener to the end of your power drill. Make sure to wear eye protection and work gloves. Carefully use the sharpener to hone the cutting edges of your blades. Go slowly at first to get the feel of the best angle for meeting the blade and sharpener.

After sharpening both sides of the blade place it on the kit's cone-shaped balancer. If one side dips below the other, continue sharpening it until the blade rests level. Return the sharpened blades to the mower and reattach. If you have a torque wrench, it's a good idea to use it here. Often you need to tighten the blade mounting bolt/bolts to a specific tightness level. 

Typically measured in pound-feet, your instruction manual should list these specs. For example my personal machine, the Honda HRR216VKA, between 36 to 43 lb-ft of torque is required. 

Run the lawn mower engine for a few minutes to get its oil flowing freely.

Chris Monroe/CNET

Step 4: Change the oil

Next you'll change the oil. To lower oil viscosity and get it moving freely, run the engine for a few minutes. Now shut the engine off and roll the mower onto a piece of cardboard or drop cloth. Close the fuel line (if your mower has one) and unhook the spark plug as before. Find the oil filler tube and remove its cap. Often the cap also functions as a dipstick.

Drain the old oil from your lawn mower into a drip pan.

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Place a drip pan or other container on the side of the mower with the filler. Carefully tilt the mower so oil drains out and into the pan. Discard the spent oil into a proper disposal vessel. 

Add the fresh oil to the lawn mower using the filler tube. A funnel like this one sometimes comes in handy, too.

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Now slowly pour fresh oil into the mower. For the specific type of oil you need, check your instruction manual. Make sure to add only as much as your particular model requires. Remember to let the mower sit undisturbed for a few minutes so the oil settles properly inside the engine.

Pour the old oil into a special disposal container.

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Get out there and mow

Now that you've done all that, your mower should be ready to tackle the season in stride. It should run smoother and more safely, too. Even better, you've just saved the $200 to $300 fee it typically costs, at least in my neck of the woods, to have your lawn mower serviced professionally. So go on and get out there. That high grass needs cutting.