How to Stop Mower Rusting (This works!)

As a mechanic, I have seen countless mowers die prematurely from rust—damage that could have been completely avoided with the right care. A little maintenance today can save you from costly repairs or even replacing your mower too soon.

Many homeowners assume their mower is built to handle moisture, but grass clippings, rain, and humidity can quickly cause corrosion. One overlooked cleaning session, improper storage, or even just a damp garage can lead to rust spots that spread like wildfire.

If you want to protect your investment and keep your mower running smoothly for years, I am here to help. In this guide, I will share my top tips as a mechanic to prevent corrosion and rust, covering:

• What causes rust on lawnmowers and why it is more dangerous than you think
• The best ways to clean, dry, and protect your mower after every use
• How to store your mower correctly to prevent rust, even in humid conditions
• What to do if your mower already has rust—and how to stop it from getting worse

Why Do Lawn Mowers Rust?

The Hidden Dangers of Rust on Your Mower

How to Prevent Mower Rust Before It Starts

Storing Your Mower the Right Way to Prevent Rust

What to Do If Your Mower Already Has Rust

FAQs

Why Do Lawn Mowers Rust?

Rust is one of the biggest threats to your mower’s lifespan and performance, and once it starts, it spreads quickly. But why does it happen in the first place? Understanding what causes rust is the first step in preventing it.

How Does Rust Form?

Rust develops when iron or steel is exposed to moisture and oxygen over time. Lawn mowers are particularly vulnerable because they are constantly exposed to:

• Wet grass clippings – Trapped moisture from freshly cut grass sits on the mower deck, accelerating corrosion.
• Humidity and rain – If your mower sits in a damp shed or garage, rust can form even if it is not directly exposed to water.
• Leftover dirt and debris – Mud, leaves, and yard waste hold moisture and can lead to rust in hidden areas.
• Scratches and chipped paint – Exposed metal from wear and tear allows rust to take hold faster.

Common Areas Where Rust Forms on a Mower

Some parts of your mower are more prone to rust than others, including:

• Mower deck – The underside gets coated with wet grass, which traps moisture against the metal.
• Blade bolts and fasteners – Small metal parts can corrode and weaken, making it harder to remove or replace blades.
• Handles and control levers – Exposed metal areas can rust from hand moisture and weather exposure.
• Wheels and axles – Mud and debris buildup can cause rust, leading to stiff or stuck wheels.
• Engine and exhaust components – While usually more resistant, prolonged exposure to damp conditions can lead to surface rust.

Why Rust is a Serious Problem for Your Mower

Some people ignore small rust spots, thinking they are just cosmetic, but rust does more than make your mower look bad.

• Weakens metal parts – Rust slowly eats away at metal, causing holes and structural damage.
• Reduces cutting performance – A rusty mower deck can disrupt airflow, leading to poor grass cutting and clumping.
• Makes maintenance harder – Rusted bolts and parts can become stuck, seized, or impossible to remove.
• Shortens your mower’s lifespan – Left unchecked, rust can destroy your mower years before it should wear out.

The good news? Rust is 100% preventable with the right care. In the next section, we will look at how to stop rust before it starts and protect your mower from corrosion.

The Hidden Dangers of Rust on Your Mower

Rust is not just an eyesore—it slowly weakens your mower from the inside out, leading to performance issues, expensive repairs, and even safety risks. Ignoring rust now could mean replacing your mower sooner than you expected.

How Rust Damages Your Mower Over Time

Rust may start as a small patch, but it spreads fast when exposed to moisture, oxygen, and wear. Here’s what happens when rust takes hold:

• Thins and weakens metal parts – Over time, rust eats away at steel, making mower decks, bolts, and fasteners fragile and prone to breaking.
• Disrupts airflow under the deck – A rusty mower deck can interfere with blade rotation, leading to uneven cutting, clumping, and poor bagging performance.
• Seizes up moving parts – Rusted bolts, axles, and wheel bearings can lock up, making the mower difficult to adjust, push, or repair.
• Spreads to the engine – While most engines are made of aluminum and less prone to rust, exhaust components and steel brackets can corrode, leading to cracks or part failure.
• Complicates maintenance and repairs – A rusted bolt or nut can become seized, making it nearly impossible to remove without cutting or drilling it out.

Is Rust Dangerous to Use on a Mower?

Yes, if rust severely weakens key components, it can become a safety risk.

• A rusted mower deck can eventually develop holes, which may cause debris or rocks to be thrown out dangerously.
• If the blade bolt rusts and weakens, it could shear off while mowing, causing serious damage or injury.
• Rusted handles and controls may snap or become unresponsive, making it harder to control the mower safely.

The Cost of Ignoring Rust

Letting rust spread can turn a simple problem into an expensive one:

• Blade replacement due to rust damage: $20–$50
• Mower deck repairs or replacement: $150–$400
• Seized wheel or axle replacement: $50–$150
• New mower due to severe rust damage: $300–$1,500+

Replacing a mower due to rust is completely avoidable with simple maintenance and protection. In the next section, we will go over how to prevent rust before it starts, so you can extend the life of your mower and keep it running like new.

How to Prevent Mower Rust Before It Starts

The best way to stop rust is to prevent it from forming in the first place. A few simple maintenance habits can keep your mower rust-free for years, saving you from expensive repairs and early replacement.

1. Clean Your Mower After Every Use

Wet grass clippings and dirt are the biggest culprits behind mower rust. When grass sticks to the underside of the deck, it traps moisture, creating the perfect environment for rust to form.

How to clean your mower properly:

• After every mow, use a stiff brush or plastic scraper to remove grass buildup under the deck.
• For stubborn clippings, spray the deck with a garden hose (avoid using a pressure washer on bearings or electrical parts).
• If your mower is gas-powered, disconnect the spark plug before tilting it to prevent fuel leaks.

2. Keep Your Mower Dry

Moisture is the number one cause of rust. If your mower sits in a damp area, rust will start creeping in—even if you never use it in the rain.

Ways to keep your mower dry:

• Store it in a garage, shed, or covered area—never leave it out in the rain.
• If you must store it outdoors, use a waterproof mower cover to protect it.
• Avoid washing your mower right before storage—always let it dry completely first.

3. Apply a Protective Coating

A little extra protection can go a long way in preventing rust. Many mechanics use coatings to shield metal parts from moisture.

Best rust-prevention coatings for mowers:

• Silicone spray or WD-40 – Forms a light protective barrier that repels moisture.
• Non-stick mower deck spray – Prevents grass from sticking, reducing moisture buildup.
• Fluid Film or Lanolin-based sprays – Excellent for long-term rust protection on metal parts.

Apply these sprays after cleaning and drying your mower, especially to the deck, bolts, and exposed metal parts.

4. Inspect for Scratches and Touch Up Paint

Even a small scratch on your mower deck can expose bare metal, allowing rust to start. Over time, these tiny spots spread and weaken the structure.

How to prevent rust from scratches:

• Check your mower deck and handles regularly for chips in the paint.
• Use rust-resistant spray paint to touch up any exposed areas.
• Apply a rust converter if you see small rust spots—this stops the corrosion before it worsens.

5. Avoid Mowing Wet Grass When Possible

Mowing wet grass not only makes mowing harder but also increases rust risk by soaking your mower in moisture.

If you must mow damp grass:

• Clean the deck immediately afterward to prevent buildup.
• Use a non-stick spray on the underside of the deck to make cleaning easier.
• Tilt the mower on its side (for electric models, follow safety guidelines) and let it air dry fully.

By following these simple rust-prevention steps, you can keep your mower running smoothly and rust-free for years.

Storing Your Mower the Right Way to Prevent Rust

Even if you clean your mower regularly, improper storage can still lead to rust. Moisture in the air, temperature changes, and poor ventilation can create the perfect conditions for corrosion. Proper storage is one of the most important steps in keeping your mower rust-free.

1. Store Your Mower in a Dry, Ventilated Space

A damp garage, shed, or basement can cause rust just as fast as leaving your mower outside.

Best storage locations to prevent rust:

• A garage or shed with good airflow
• A covered porch or patio (if a garage is unavailable)
• A weatherproof storage box or mower tent for outdoor storage

Avoid storing your mower directly on concrete—concrete retains moisture and can cause condensation to form on metal parts. Instead, place a wooden board or rubber mat under the mower.

2. Use a Mower Cover for Extra Protection

If you must store your mower outdoors, a waterproof, breathable cover is essential.

What to look for in a good mower cover:

• Waterproof material to keep rain and humidity out
• Breathability to prevent condensation buildup
• UV resistance to protect plastic and rubber parts from sun damage

Avoid using plastic tarps for long-term storage, as they trap moisture inside, speeding up rust formation.

3. Keep Your Mower Off the Ground

Raising your mower slightly off the ground helps improve air circulation and prevents moisture from pooling underneath it.

• Use a small pallet, shelf, or stand to lift the mower a few inches off the ground.
• If storing for winter, consider placing moisture-absorbing packets or silica gel nearby to keep the air dry.

4. Empty the Fuel Tank Before Long-Term Storage

Old fuel absorbs moisture over time, which can lead to rust forming in the fuel tank and carburetor.

• If storing for more than a month, run the mower until it is out of fuel or add a fuel stabilizer.
• For electric mowers, remove the battery and store it in a dry place to prevent corrosion.

5. Avoid Storing a Wet or Dirty Mower

Even if you store your mower in the best conditions, putting it away wet or covered in grass clippings invites rust.

Before storing your mower:

• Clean and dry it thoroughly.
• Apply a light protective spray (like WD-40 or silicone spray) on metal parts.
• Lubricate moving parts like wheel axles to prevent stiffness.

What If You Have No Garage or Shed?

If indoor storage is not an option, try these alternatives:

• Invest in a waterproof mower storage box or deck storage container.
• Use a mower tent or heavy-duty outdoor cover.
• Keep it under an overhang, covered patio, or lean-to shelter to protect it from direct rain.

Proper storage greatly extends your mower’s lifespan and keeps rust at bay. Next, let’s cover what to do if your mower already has rust—and how to stop it before it spreads.

What to Do If Your Mower Already Has Rust

If your mower has already started to rust, do not panic—you can stop the damage and prevent it from getting worse. The key is to act quickly before rust spreads and weakens the metal.

Step 1: Assess the Rust Damage

Before removing rust, check how severe it is:

• Surface rust – Light rust that has not eaten through the metal. It looks like an orange or brown stain and is easy to remove.
• Moderate rust – More noticeable rust buildup, possibly with some pitting in the metal but no holes. This can still be cleaned and treated.
• Severe rust – Rust that has corroded through the metal, causing structural weakness. In this case, parts may need reinforcement or replacement.

Step 2: Remove Rust from the Mower Deck and Metal Parts

For surface rust and moderate rust, use these methods:

Option 1: Wire Brush and Sandpaper

• Use a wire brush or medium-grit sandpaper to scrub off loose rust.
• If needed, follow up with fine-grit sandpaper to smooth the area.

Option 2: Rust Dissolver (For Stubborn Rust)

• Apply a rust remover or white vinegar and let it sit for 10-15 minutes.
• Scrub with a brush and rinse with water.
• Dry the area completely before applying any coatings.

For severe rust where metal has holes or is flaking apart, consider:

• Metal patching compound for small holes.
• Replacing severely rusted parts if they compromise safety.

Step 3: Apply a Rust Converter or Protective Coating

Once the rust is removed, you must seal the metal to prevent future corrosion.

• Use a rust converter spray or primer to stop any remaining oxidation.
• Apply a rust-resistant paint (like outdoor enamel) on the mower deck and exposed metal parts.
• Finish with a protective spray like WD-40, silicone spray, or Fluid Film to repel moisture.

Step 4: Maintain and Prevent Rust from Returning

• Keep your mower clean and dry after each use.
• Apply a deck spray or rust inhibitor after cleaning.
• Check for rust spots regularly and treat them before they spread.

When to Replace Rusted Parts

If rust has:

• Created holes in the mower deck, weakening its structure,
• Made the blade bolts unsafe to remove or tighten,
• Severely corroded handles, wheels, or axles,

…then it may be time to replace those parts for safety and performance.

Rust does not have to ruin your mower—with the right steps, you can restore and protect it for years to come.

FAQs

1. Can I use cooking oil or vegetable oil to prevent rust on my mower?

While some people use vegetable oil as a temporary rust barrier, it is not the best option because it can become sticky, attract dirt, and break down over time. Instead, use:

• Silicone spray or WD-40 for moisture protection.
• Non-stick mower deck spray to prevent grass buildup.
• Lanolin-based products (like Fluid Film) for longer-lasting rust prevention.

2. How often should I check my mower for rust?

It is best to inspect your mower after every use, but at a minimum, check:

• Before and after the mowing season (spring and fall).
• Every few weeks during peak mowing season, especially if mowing wet grass.
• After washing or exposure to rain—always dry the mower completely.

3. Is it okay to store my mower outside if I do not have a garage?

Yes, but you must take extra precautions:

• Use a waterproof, breathable mower cover (not a plastic tarp, which traps moisture).
• Elevate the mower off the ground to prevent water from pooling underneath.
• Apply a protective spray (like WD-40 or silicone) to exposed metal parts before long-term storage.

4. Can I prevent rust by waxing my mower?

Yes! Automotive wax can help protect the painted surfaces of your mower from moisture and oxidation.

• Apply wax to the top of the mower deck and metal frame after cleaning.
• Avoid getting wax on the underside of the deck, as it can make it slippery.
• Reapply wax every few months for continuous protection.

5. Is rust on my mower deck dangerous, or is it just cosmetic?

Rust starts as a cosmetic issue but can become a serious problem if left untreated.

• Minor surface rust is not a major issue if caught early.
• Moderate rust can cause airflow disruptions, leading to uneven cutting and clumping.
• Severe rust can weaken the deck, causing holes and making it unsafe to use.

If rust has eaten through the mower deck, it is time to replace it or reinforce the damaged area to prevent safety hazards.

You may also find the following posts helpful:

Winterizing mower video

Adding gas stabilizer video

Storing your mower