The Real Reason Your Lawn Mower Is Vibrating (And How To Fix It)
When you do lawn mower maintenance tasks after every mow, it helps to keep the machine in great condition and running smoothly. However, even the most well-cared-for, highest-quality lawn mower will eventually have problems and begin to wear out. One of the signs that something is wrong with the mower and it may need repairs or additional maintenance is excessive vibration. When the mower is shaking while you're trying to use it, it's uncomfortable to use. Continuing to use it in this condition could lead to additional damage.
Although vibrating lawn mowers can have multiple causes, one of the most common is a bent, cracked, or unbalanced blade. You might bend a blade by hitting a tree stump, a curb, or rocks. Even if the blade doesn't have a noticeable nick, dent, or bend, you may have hit a hard object and knocked it out of balance, which leads to vibrations. Signs of this might be uneven wear. If you have a bent or out-of-balance blade, the easiest option is to replace it. Attempting to straighten it might lead to additional problems. You can expect to pay $50 or more for a new blade. If you prefer to try to straighten it yourself, tilt the mower on its side and remove the nut holding the blade in place. You can then use pliers or a hammer to try to straighten the metal. To achieve the best results, secure the metal with a vice or clamp to hold it steady.
Other common causes for excessive vibrations in a walk-behind lawn mower
If you have an older lawn mower, it may begin to vibrate excessively because of worn parts. Even if you buy a top-rated self-propelled lawn mower with noise reduction capabilities, it could eventually end up with vibration problems that you need to watch for and potentially repair. (Always disconnect the spark plug wire before working on any part of the machine.)
If the blades look fine on the mower, another common cause for a vibrating walk-behind lawn mower is parts that are loose. As you operate the mower, parts may start to come loose from slight vibrations. Eventually, those loose parts create stronger vibrations and further loosen the parts. Tighten the fasteners on the handle to reduce vibrations and replace any bolts and nuts that are missing. Check and tighten the bolt on the mower blade with a torque wrench. Inspect the entire machine for any other loose bolts.
Other problems with push lawn mowers that can cause vibrations are structural in nature. If the mower deck has any cracks or warping problems, it can lead to shaking from clogged grass clippings sticking in the damaged section of the deck. If you strike something solid, it could bend the crankshaft, leading to significant vibrations. Look at the bolt that holds the blade in place underneath the deck. Keeping your fingers and hands away from the blade, pull the starter rope slowly and watch the bolt. If it appears to wobble instead of spinning smoothly, the crankshaft is bent and almost certainly needs replacing.
How to deal with a riding lawn mower that has excessive vibration
Even the best riding lawn mowers you use to cut your grass could eventually suffer from excessive vibrations. Some vibrations may relate to the machine's belts. The drive belt transfers power from the engine to the wheels, while the deck belt spins the cutting blades. When a drive belt begins to lose tension or alignment, it can cause vibration throughout the machine. A worn deck belt will not spin the blades evenly or smoothly, leading to significant vibrations. If you see wear on either belt, it needs replacement.
As with push mowers, bent blades can cause vibration in a riding lawn mower. Most riding mowers have two or three blades, so it's important to inspect all the blades for damage. It's best to replace the bent or damaged blade with a new one to stop the vibration.
A riding lawn mower deck spindle problem could lead to vibrations, too. The spindle holds the blade in place in the deck and allows it to spin properly to cut the grass. If the spindle has cracks or is bent, it can generate significant vibrations. To replace it, remove the deck, belt, and blade from the riding lawn mower. The spindle attaches to the deck with bolts that you can loosen with a wrench. Attach the new spindle and replace the blade, belt, and deck. If the deck's metal is rusted or torn where the spindle attaches, the deck needs repair or replacement.