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I Forgot To Winterize My Lawn Mower! (Now What?)

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Last updated on August 14th, 2022 at 01:24 pm

If you forgot to winterize your lawn mower, don’t despair! Even if you don’t have the right tools, it’s possible to do it yourself in the comfort of your garage with just the tools you already have on hand.

This article will guide you on how to winterize your lawn mower quickly and efficiently so that your mower will be ready to start up again as soon as spring rolls around!

If you forgot to winterize your lawn mower, have no fear that your lawn mower won’t start. It is something that you can fix yourself, check the oil level, spark plug, and fuel in the tank. However, know that you should winterize your lawn mower to prolong its lifespan and avoid problems.

I Forgot to Winterize My Riding Lawn Mower 

I Forgot to Winterize My Lawn Mower

As the cold weather sets in, you may wonder why your gas lawn mower won’t start.

If you forgot to winterize your lawn mower, don’t worry – there are a few things you can do to get it up and running again for the lawn mower season. 

  • First, check the oil level and make sure it’s complete. 
  • Check the spark plug and clean it if necessary. 
  • Make sure there’s gas in the tank.

When you leave gas in a lawn mower over time, it can become a thick sludge. That sludge can clog up your air filter and fuel lines and prevent your lawn mower from starting.

If you’ve run out of gas or can’t get your lawn mower to start, pour fresh gasoline into the tank (it’s okay if there’s still some old gas in there). 

Then, ensure that you have enough oil in your engine—about one quart should do it.

Next, let your lawn mower sit for about 10 minutes before trying to start it so that the oil has time to spread throughout the engine. 

You might also want to put a small amount of STP motor treatment in with your new gas, which will help keep debris from building up inside your lawn mower during this season when you aren’t using it as often.

Finally, be sure not to store your lawn mower with any gas inside! These same steps will work if you have a gas lawn mower, but be aware that it might take your lawn mower longer to start.

You can avoid problems with your lawn mower not starting in cold weather by using warm-up procedures each time you use it.

Before you start your lawn mower, let it sit for a few minutes and run until all of its parts are warm.

What Happens If You Don’t Winterize Your Lawn Mower?

Winterizing your lawn mower is very important for the lawn mower to start during the lawn mower season.

However, if you forget to winterize your lawn mower and find out that it’s not responding, here are some possible causes listed in the table below why it isn’t starting.

Possible CausesHow it Happens
CorrosionIf you don’t winterize your lawn mower, it leads to corrosion in your mower. Oxygenated gas with ethanol is particularly hazardous for this as ethanol soaks up water. When this happens, the fuel tank, carburetor,  fuel lines, and cylinders can corrode. White “crusty” deposits on metal are a sign of corrosion; corroded particles obstruct the carburetor.
Stale GasIf you leave old gas in your lawn mower for a while, the parts will start to break down. Some leftover gas bits will look like gum once they have broken down. This substance will coat the lawn mower’s engine and clog the carburetor, making it impossible to start.
Lower LifespanIf you do not winterize your lawn mower, it results in a lower lifespan than those winterized. A winterization helps protect your lawn mower.
Difficulty in StartingCorrosion and gunk in your lawn mower can prevent it from starting or cutting off. Hence, winterization of your lawn mower is needed.
Less Efficient & Requires More MaintenanceNot winterizing your lawn mower can result in developing issues, and it won’t work as well as before leading to constant maintenance.

Is It Necessary to Winterize a Lawn Mower?

Yes, it is necessary to winterize your lawn mower. Lawn mowers are expensive, and if you don’t take care of them, they won’t last as long.

Winterizing your lawn mower will help it last longer, perform better and prevent costly repairs. You expose your lawn mowers to more precipitation and moisture in cold weather.

The salt on snowy roads and sidewalks can cause severe damage, especially if you don’t store your lawn mower appropriately during its off-season.

It would be best if you did all you could to protect your investment, whether a new or used lawn mower; hence winterization is necessary.

Winterizing a lawn mower involves adding a fuel stabilizer to the gas tank, draining the oil, and disconnecting the battery.

These steps will help ensure your lawn mower starts up again in the spring. Winterizing your lawn mower is also essential for safety reasons.

If you live in a cold area, if you accidentally left your lawn mower outside during freezing temperatures could cause severe damage. Lawnmowers can also rust and corrode.

Some parts of your lawnmower may be difficult to clean during regular maintenance.

These parts will get clogged with dirt and grass and are hard to reach when working on your lawn mower. Winterizing will help keep these parts in good condition.

If you live in a hot climate, leaving your lawn mower outside in temperatures over 80 degrees could cause severe damage.

Leaving it outside for too long can also cause rusting and corrosion of lawn mower parts.

How to Winterize a Mower: (Step by Step)?

You now know it is necessary to winterize your lawn mower to prepare it for the following lawn mower season.

But how do you go about that? Below is a step-by-step guide on how to winterize a lawn mower.

#1. Disconnect the Power

Firstly, disconnect your lawn mower as a safety precaution when winterizing it. Even when it’s not running, lawn mowers can sputter, and it’s easy for the person using them to get seriously hurt in a matter of seconds.

Even though electric lawn mowers work differently, the risks are the same if you accidentally press the power button.

If you’re working on a gas lawn mower, remove the old spark plug and lay the mower on its side with the air filter facing up.

Don’t forget to take the battery out of an electric model before you start working on it.

#2. Clean the Deck

Cleaning the lawn mower deck after every use would be best to ensure the blade works well.

It is even more critical before winter because it will stop moisture from causing problems like rust or a future performance drop.

To clean the deck, you’ll have to work around the blade to clean the deck, so you should be careful.

If the grass clippings wedged to your lawn mower are recent, you can quickly get rid of them with a pressure washer, garden hose, and all-purpose cleaner.

If they’re already dry, you’ll need a pot scourer or a plastic paint scraper to help you get them off.

If you’re working close to the blade, wear work gloves. To stop buildup from happening again, spray the underside with silicone spray.

#3. Drain the Fuel Tank

Gas has a three-to-six-month shelf life. You should drain the stale or old gas as soon as possible and put in fresh fuel, as it can damage your lawn mower. It can also damage your carburetor and damage rubber seals.

If you don’t want to waste your mower’s gasoline, apply a fuel stabilizer to keep it fresh. Check your mower’s specs and user manuals for clear instructions before purchase.

#4. Change the Oil

Motor oil can resist heat and pressure while collecting debris and cooling the motor. When these pieces of trash pile up, they can start to break down your lawn mower.

To replace your mower’s oil, you will first need to take out the drain bolt, retrieve the old oil, put the drain bolt back in its place, and fill the mower with the type of oil recommended for your mower.

Changing the oil in a lawn mower isn’t just something you should do once in a while. After every 50 hours of use, ensure you change the oil.

#5. Change the Filters

A lawn mower can have one to three filters, with most having fuel line filters, whereas four-strokes also have oil tank filters and air filters.

Fuel filters are needed to keep small pieces of dirt and debris from getting into the gas, but they can get congested over time.

When this happens, fuel flow to the mower motor slows down, and the engine runs out of gas.

Block the petrol tank before changing the fuel filter using pliers, remove its clips and change the filter.

Oil filters act like fuel filters, but they clean your lawn mower’s oil; these filters screw onto the side or the lawn mower motor. Unscrew and replace the filter by hand.

#6. Sharpen the Blade

A dull blade may cut, but it mashes grass strands together. This damage slows development, allows infections, and generates brown grass patches.

On the other hand, a sharp blade cuts grass blades cleanly, promoting healthy lawn growth.

It would help if you regularly sharpen your lawn mower blades, either while mounted or after removal.

First, turn the mower on its side while filing, so metal filings fall instead of the blade’s shaft. Then, use a manual file or rotary device with a grinding attachment to sharpen the blade.

#7. Lubricate moving parts

Consult your lawn mower’s owner’s manual for lubrication requirements to prolong its life. Lawn mowers have several holes that catch dirt and debris.

Periodic cleaning of your mower might cause rust and harm. Handles, wheels, levers, and axles are often dirty.

Dirt can become an annoyance if left uncleaned. Instead, apply light machine oil or 3-in-1 oil after cleaning your mower.

#8. Check the Cables

Worn throttle cables can kink, and they rub on guides. They can wear through the coating and cause corrosion.

Replace worn guides; it’s fast and cheap. When the throttle cable’s thin wires come loose, it stabs you in the finger; it’s unpleasant but not severe.

Check the electric lawn mower cables for damage. Cracks or splits require replacement.

In addition, exposed wires might produce short circuits that trip breakers or stop the mower, resulting in an electric shock.

#9. Please Take Out the Battery and Put It Away Inside

For people with electric riding lawn mowers or lawn mowers that don’t have cords, take out the batteries of your mower to keep the temperature from changing too much.

Cold weather could drain a battery’s power if left plugged in. If you store your mower where it gets cold enough to freeze, you should take the battery out and put it somewhere warmer.

#10. Check Mower’s Spark Plug and Condition

Unscrew, pry out the spark plug with a socket wrench, and examine its end; if it’s dusty or corroded, replace it.

Check your lawnmower’s overall health as you inspect it. Before putting the mower for the winter, address any rust, corrosion, or other degradation indicators. The problem will worsen after winter.

Can You Winterize a Lawn Mower Yourself?

Yes, you can winterize your lawn mower yourself; it should take an hour or more. Of course, you can also decide to take it to a repair shop, but it’s something you can do yourself with just a little bit of time and the right supplies.

If you have no idea where to start, follow the steps in the article and prepare for the next lawnmower season.

Is It Okay to Leave Gas in Mower over Winter? 

No, leaving gas in your mower through the winter can hurt the engine and tank. It can break down and jam up your carburetor and speed up rusting inside the tank.

Also, if you use unprepared gas, it can cause the engine to fail terribly. Gasoline’s chemical combination burns in the machine to power the lawn mower.

Unfortunately, this mixture includes ethanol, and due to its volatile nature, ethanol quickly evaporates and attracts humidity.

As a result, this leads to two problems. 

  • First, evaporation degrades fuel. Stale fuel hardens, clogging your carburetor with muck.
  • The second is corrosion. The aluminum inside the tank can rust if there is more water vapor inside the tank than usual. Rust mixed with gas might damage the engine as old gas can rust the lawnmower’s carburetor.


In conclusion, winterizing your lawn mower is crucial to its lifespan as it is costly, so replacing it won’t be an option.

However, if you forgot to winterize your lawn mower, fear not! You can rectify it, follow the steps in the article and ensure you winterize it in preparation for the next lean mower season.

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