Protecting your mower from the elements is crucial to getting the most out of what is — at least to most — a big financial investment. So, despite the fact that lawnmowers can technically get wet, the reality is that they shouldn’t.
In this article, I’ll explain how moisture can impact a lawn mower and what to do if your machine falls victim to unexpected rain or a night accidentally left outside.
Can Lawn Mowers Get Wet?
Lawnmowers are designed to get wet. After all, it’s impossible to keep any piece of equipment meant for outdoor use 100% dry at all times. But that doesn’t mean you should leave your lawn mower out in the rain or operate it in standing water.
While lawnmowers are designed to tolerate some water, it’s important to note that mowers exposed to prolonged moisture of any amount are more likely to show signs of wear and tear. You won’t always experience the consequences of a lawn mower getting damp immediately.
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Wet Lawn Mower or Damp Lawn Mower
To be fair, most people know that lawnmowers can handle a small amount of moisture. The real question is how much water exposure is enough to cause problems.
In a perfect world, I’d ensure my lawn mower stayed dry at all times. Of course, that’s just not possible. Between morning dew, unforecast rain, and the moisture naturally found in cut grass blades, the only way to keep a lawn mower 100% dry is to keep it in storage and never use it.
Speaking of perfection, we all make mistakes. I’m certainly guilty of leaving my lawn mower outside overnight. However, there’s no need to panic if you accidentally expose your mower to excess moisture.
Here are some common scenarios that might result in a wet lawn mower and what you can do to minimize potential damage:
Mower Left Out in The Rain
We’ve all done it: You take a break from mowing the lawn with the full intention of going back out in an hour or so to finish the job. Then the day gets away from you and suddenly your lawn mower has been sitting outside for hours on end.
Generally, this wouldn’t be a problem. But that can change if your area experiences rainfall while your mower is left sitting outside.
Heavy rain can soak a lawn mower in a matter of minutes. To dry off the housing as quickly as possible, you can place the mower in the sun or run the engine to create heat. However, keep in mind that the rain may have penetrated past the exterior housing and into other parts of the mower.
Mowing Waterlogged or Wet Lawns
Mowing wet grass is never a good idea. Not only can the excess moisture cause damage to your mower but operating heavy equipment on damp grass can seriously damage the lawn.
If you do use your mower on a wet lawn, the underside will naturally be exposed to the most moisture. After mowing, I recommend carefully removing any stuck grass clippings from the blades, wheels, and other parts. Ensure the mower is fully dry before returning it to storage.
Leaving a Mower Outdoors on a Damp Night
Storing your mower outdoors on a dewy night can produce similar results to leaving it in the rain. While a single night like this is unlikely to cause serious damage, you’ll want to keep an eye on lawnmowers that are regularly stored outside.
To prevent rust and engine damage, set the mower out in the sun or run the engine for a short period first thing in the morning.
If for some reason you can’t store your lawn mower indoors, I strongly suggest investing in a waterproof tarp to protect it from the elements. I also recommend lifting the mower up on a wooden pallet or similar structure to keep it away from standing water.
Problems with Lawn Mowers Getting Wet
Moisture can damage a lawn mower even if it doesn’t penetrate into the engine itself. This is one of the reasons why mowing wet grass is never recommended.
Rest assured, you don’t need to fear every drop of water your lawn mower may come into contact with. But, to prolong the life of your equipment, I strongly suggest avoiding moisture as much as possible and drying all accessible parts of your mower after each use. Failure to do so can lead to a number of problems — not limited to electrical failure or metal corrosion.
Electric Mowers Don’t Like The Wet
While electric lawnmowers grow in popularity, it’s important to remember that they are just as susceptible to moisture damage as gas-powered ones. If water comes into contact with exposed wire connections it could send off an electric shock. According to Bob Vila, the lawn mower’s user is also at risk of electrocution if this occurs.
Older electric lawnmowers with signs of wear and tear are particularly vulnerable to water exposure. There may be unseen damage to wires that allows moisture inside.
If your lawn mower relies on a power cord instead of a battery, you also need to take that into consideration. Extension cords should be inspected for damage before each use.
Corrosion
Another common problem seen in wet lawnmowers is corrosion or rust. Corrosion damage may occur on the exterior housing of your mower or deep within the engine.
Corrosion can even be a problem on parts that are designed to otherwise hold up to the elements. Wheels and related parts may rust after prolonged water exposure, especially if the enamel is chipped or damaged.
Over time, corrosion can cause a variety of issues. It can break down the metal housing of your mower, leaving the interior more vulnerable to damage. Rust buildup on wheels and axles may impact how easily your mower drives and steers. Corrosion can also damage the blade system, putting extra strain on the motor and interfering with the quality of each cut.
Problem with Damp or Moisture Ingress
In my experience, moisture ingress can do far more damage than corrosion or immediate engine failure. You may put your lawn mower back into storage without realizing that it needs to be taken apart and dried. But the next time you attempt to use your mower, the fact that water has infiltrated the engine will be painfully obvious.
Engine Cutting Out
After rescuing your mower from damp conditions, watch out for problems like the engine failing to start, running slowly, lacking power, or stopping unexpectedly.
Most of these issues can be narrowed down to one or more components inside the mower’s engine:
Spark Plug
Condensation can accumulate on a mower’s spark plug and prevent it from igniting the fuel inside the engine. Checking a spark plug is relatively simple, and should be the first place you start after leaving your lawn mower out in the rain or morning dew.
Remove your mower’s spark plug and inspect for moisture. Along with drying off the plug with a paper towel or rage, you can use a piece of sandpaper to clear away any noticeable buildup. Allow the spark plug to completely air dry before reinstalling it.
Fuel Tank and Carburetor
Water entering a lawn mower’s fuel tank is one of the worst-case scenarios. With a little work and patience, however, it is fixable.
When checking for water infiltration in your mower’s fuel tank, look for small bubbles that sink to the bottom of the gasoline. If bubbles are present, you will need to disassemble and dry all of the engine components. Be sure to refill the fuel tank with fresh, uncontaminated gasoline.
Air Filter
A wet air filter won’t work properly. Before starting your lawn mower, I recommend removing and inspecting the filter. Set the filter out to air dry if it has gotten damp — this is also a good time to clean the filter.
Foam air filters should be re-coated with a small amount of fresh motor oil once dry. If your lawn mower uses a paper air filter, excess moisture could damage the filter to the point of needing a replacement.
Electrical Failure
Electric lawnmowers typically have water-resistant casings around their motors to prevent moisture damage. If water does manage to infiltrate the engine, however, you may notice similar problems as those described above — i.e., failure to start, weak power, and unexpected stops.
Before operating your lawn mower after water exposure, I recommend disassembling and drying out all accessible parts of the motor. Use an electrical contact cleaner to remove dirt and condensation from sensitive parts.
What To Do If Your Wet Lawn Mower Won’t Start
The first step when starting any wet lawn mower is to spray starter fluid in the carburetor. This is recommended regardless of engine problems.
If your lawn mower still fails to start, don’t panic. There are several more things you can do to undo moisture damage within the motor:
- Drain and replace existing oil and gasoline
- Replace the spark plug
- Check the coil for rust and clean it with sandpaper if needed
While the above steps work in most cases, prolonged moisture exposure could do, even more, unseen damage. I recommend reaching out to a professional engine repair service if your lawn mower still fails to start.
Can You Mow In The Rain – Is it Safe
You may be tempted to mow your lawn in the rain, especially if you have a packed schedule. However, there are exactly zero benefits to cutting wet grass and numerous potential drawbacks.
Mowing damp grass can do serious damage to your lawn as well as your equipment. Not even the sharpest blade can achieve a straight cut when the grass is heavy with water. Driving or pushing a lawn mower on waterlogged soil can also cause severe compaction.
If that wasn’t reason enough to reschedule your lawn maintenance to a dry day, mowing wet grass can be dangerous. You’re more likely to slip and fall while operating your mower. There’s also a risk of electric shock if your lawn mower relies on a battery or extension cord for power.
Solved: Can Lawn Mowers Get Wet
The average lawn mower doesn’t need to be kept dry 100% of the time. With that said, preventing unnecessary moisture exposure is one of the best ways to prolong your mower’s life expectancy and avoid expensive repairs. Also, your lawn mower should never be left outside during heavy rainfall or operated in areas with standing water.
