As part of any lawn mower’s regular maintenance and care, you should sharpen or replace a lawn mower’s blades once or twice every season or so, depending upon how much you use your mower. A sharp mower blade cuts your lawn cleaner while a dull blade can actually “rip” and pull at your grass, actually damaging the plant itself, making your grass turn brown and be more susceptible to disease. A dull mower blade can also force your lawn mower to work harder to cut the same amount of grass, which can actually increase your fuel consumption.
You can actually tell if your lawn mower blades need to be replaced or sharpened by simply taking a good look at your grass after you cut it. If you the ends of the grass blades look ragged (compare it to a few blades of grass your cut with a pair of scissors) or if the ends of your grass blades are turning brown a day or two after cutting, then your blades are probably due to be replaced or sharpened. Obviously, if you accidentally hit something hard like a big rock or metal pipe with your mower blade while it’s running then you might want to replace the blade for safety’s sake. A nicked or unbalance blade can be dangerous and can, in rare cases, actually break while running.
Put on some gloves, find the right combination wrench, and turn to the left to remove your lawn mower blade. Grunt when appropriate.
You can sharpen the blade yourself, but if you go that route you’ll probably need a grinder and at least a little bit of practice and skill to get your blade sharpened and balanced just right. The cost of having your blades sharpened at a mower shop can be anywhere between $15 to $30, which is about what it costs to replace most common lawn mower blades. I usually choose to replace my mower blades because the cost is the same and it’s actually a pretty quick weekend home improvement project once you’ve done it a couple times. I usually choose to replace the blade when I pull my lawn mower out and get it started the first time each Spring.
So put on some heavy duty gloves, grab an adjustable wrench and maybe a rubber mallet. Here’s how you remove and replace most lawn mower blades:
1. Disable the Mower: For safety’s sake you need to make sure your mower cannot start in any way, shape or form. The quickest way to do this is to remove the spark plug or at least detach the spark plug cord so that your engine can’t get a start, even if you hit the ignition switch or manage to pull the cord accidentally.
Blocking the lawn mower blade from turning with a block of wood. The other end of this piece of lumber is tightly wedged into the ground.
2. Remove Any Gasoline or Oil: You’re going to have to tip your lawn mower on it’s side, so that means liquids in your mower, like gasoline and oil, will most likely spill out. You can siphon the gasoline out of your tank easily with an affordable gas siphon
3. Secure the Lawn Mower and Mower Blade: Now you can put your lawn mower on it’s side. You might want to secure it with some blocks or place it on a workbench so it’s easy to get to. I tend to secure mine with some concrete landscaping bricks. While it’s on it’s side, clean out any dry grass or other debris so you have a fairly unobstructed work area. You’ll also want to secure your lawn mower blade because as your turn the single bolt that holds on your blade you can bet that the blade will turn, too. There are a couple ways to do this, but the most basic is to lodge a two-by-four or block of wood into the mower deck so that the blade turns and then stops and is held against the block. I always set my mower on it’s side in my driveway (easier to spot and clean up any errant oil or gas drips) and then I prop a block of wood against my driveway and the mower deck. It’s kind of crude, but secure.
4. Remove the Mower Blade Bolt: Now you can use a wrench to loosen the nut or bolt holding on your lawn mower blade. It should be a simple “lefty loosey” sort of turn, but you might need to put some strength into it if it’s been a while since your blade was put on. This is where the rubber mallet can come in. You may need to use a combination wrench or press the wrench against the bolt and bang it a few times with mallet. Still not working? I’ve had good luck on all sorts of stuck screws and bolts with Liquid Wrench
Old vs. New Lawn Mower Blade. It was clearly past due.
5. Replace or Sharpen Your Blade: If you really want to sharpen your blade, go for it. If you want to replace your blade you can now take this old blade to your local hardware store and just find a replacement blade. If you know your mower make and model you can measure your blade with a tape measure and save a few dollars by ordering your lawn mower blade online
6. Put Your Mower Blade Back On: Now that you have a new (or sharpened) blade you can put it back on, reversing the steps you took in the last step. Make sure your mower blade is put on with the sharp edge pointing in the right direction and make sure you put your blade back on with all the appropriate washers. Hand tighten and give the mower a spin or two with your hand, to make sure everything is working well.
Okay, you’re done! Flip your lawn mower back over, gas it up, check the oil, attach the spark plug cable and give it a whirl. If you didn’t attach the blade correctly or it’s unbalanced then your mower may vibrate and shake much more than it did before. Even a slight vibration can be dangerous and can affect the long-term durability of your lawn mower, so stop everything and go through the whole process again. You can use a nail that’s driven straight into a wall as a balancing tool, or you can use a little tool made for balancing lawn mower blades
Remember: replacing your lawn mower’s blades is one of the many ways you can maintain your lawn mower and keep it running well all year long! When it’s time to put your mower away for the season, don’t forget to winterize your lawn mower properly!
Thanks! Got it done!
I have a Honda commercial hra-216 and it is old. I am trying to replace the blade but all it does is turn around. The bolt is tight but feels like the inner part that turns the engine is turning to. How do i stop the engine mechanism from turning to loosen the bolt to get the blade bolt off? Thanks for any help please….
Ron, if you can stop the blade from rotating then you should be able to turn the bolt. If everything is “stuck” and the blade is turning, then yeah, you’ll actually be turning over the engine, too. For my mower I just use a big block of wood wedged in there so it that the blade can’t turn anymore.
Having a problem with my mower blade. When I put it on and tighten the blade, it spins off when I start the mower. I have put a lock washer on but the mower engine runs counter clockwise and just spins the blade off. Anybody know what to do? Thanks
Dave,
Huh, that’s odd. Most mower blades (and small engines) turn clockwise. Most bolts will loosen off with a counter-clockwise rotation. If the blade turns counter-clockwise then I would have guessed the bolt would have to tighten with a clockwise rotation. I’m not sure how else it could all work. A mower blade spinning off the shaft sounds awfully dangerous. Can you look up the model number online and try to find a manual? Without seeing it, I’m sort of stumped myself… Let us know if you find something!
I’am having same problem as Dave. Replaced blade by screwing in bolt clockwise but when pull the cord blade spins counter clockwise and falls off.Any thoughts. Thanks.
I just changed my mower blade but didnt empty the gas and now my mower wont start…i tried it the first day then the second day but to no avail. What do you think the problem is?
Terry
Terry,
I’m not exactly sure, but you could have accidentally introduced some sort of debris or blockage into the fuel line. You can try to follow these tips for starting a lawn mower to see if they help at all.
I’m hoping you DID remember to put gas back in the mower if any spilled out! Good luck!
Hey guys, I know summer is just around the corner, & with that in mind I must say two (2) mower blades for us (with a Crapsman & a Toro) 4 each machine is SOOOO helpful! ALSO, I just use a “C” clamp clamped to the side of the mower to hold the blade still when I loosen (lefty) or tighten (righty) it Works so much better than a stick which anyone knows if sharpened goes in the EYE…..LOL RON
I came here to find out which way to turn the bolt and yes it is counter clockwise. I also followed the tip on putting a 2×4 in there to stop the blade from turning and nicely bent the blade rendering it useless! You shouldn’t give advise here if you dont know what you are doing.
Mike,
If you actually bent your mower blade by turning it against a 2×4 then I’m pretty sure you’re doing it wrong. Honestly, I have no idea where you got such a soft and flexible mower blade. You probably shouldn’t be working on lawn mowers or trying work on lawn equipment unless you know what you’re doing. I suggest you pay someone to maintain your mower for you in the future.
Tom,
You take a lot for granted when you say that I did it wrong and I don’t know what I am doing. I worked as a contractor with my father age 14 – 21 and have worked on cars, houses, boats since. I am now 51 years old and think I am damn qualified to replace a mower blade! I thought you had a good idea there wedging the 2×4 in there and yes maybe my blade was thinner than most. I like Ron Kliens idea much better using a c clamp. I came to this site because I was not sure which way to turn the bolt on my Poulan Pro. I would add that I put a pipe on the end of a box wrench for more leverage to finally get the bolt off and remove the now bent mower blade. The wood wedged in there puts too much stress on the blade and should be completely avoided. Why take a chance or just hold the blade with heavy gloves like I did.
Regards,
Mike
Tom, I just purchased a new blade for my Poulan push mower. It appears to have a Teflon-like coating on the entire surface, so the cutting edge is not very sharp. No instructions on the blade, and the Lowe’s guy was unsure whether or not I needed to sharpen the cutting edges. Your thought?
Richard: Nope, you shouldn’t have to sharpen the blades on a new mower. They may not feel “razor sharp” but they don’t have to be to cut grass. Someone once mentioned this to me: Weed wacker cord isn’t sharp (it’s actually tubular/round) but it cuts grass quick and evenly.
Mike: I’ve used the wood wedge many times with no problem… I’m not an expert in every mower on the planet… I’m just a guy showing people tricks that I’ve picked up through experience and others… that being said, I agree with you: A C-clamp sounds like a great idea! (provided you don’t tighten it so much that you bend the blade housing).
The next time I replace my blades I’ll see if I can try the C-clamp idea and post photos or video!
Ive heard most mowers can be turned on their side, without removing the oil or gas, but you must lift from the carburetor side so your fluids have no openings to flow out of. Lifting from the non carburetor side would likely flood you engine and kill you air filter.