8 Common Lawn Mower Problems

Lawnmowers are essential tools for garden care, especially during the growing season. Like any mechanical equipment, they require proper use and upkeep to function reliably. Over time, wear and tear or simple maintenance oversights can lead to common problems that affect how well your mower performs. From engines that won’t start to uneven cuts or unusual smoke, these issues can be frustrating if you’re unsure what’s causing them.

Knowing the signs early can help prevent bigger repairs down the line. In this blog, we’ll explain some of the most common lawn mower problems, what might be behind them, and how regular maintenance and professional repair services can keep your mower in top condition.

1. Mower Won’t Start: What Could Be Causing the Silence?

One of the most common issues homeowners face is a non-starting mower. Often, the problem lies in simple but overlooked components.

If your mower doesn’t roar to life after several pulls or attempts, it might be due to:

• Stale fuel: Over months, old petrol left in the tank can degrade and clog internal components.
• Faulty spark plug: A worn-out or dirty spark plug can prevent ignition.
• Clogged carburettor: Dirt and fuel residues can build up and stop fuel from reaching the engine properly.
• Disconnected or dirty air filter: The engine won’t start or run efficiently without proper airflow.

Regular servicing and lawn mower maintenance can help prevent these issues by keeping all essential components clean and functioning properly.

Engines can overheat even under regular use, especially during the warmer months. It could be a warning sign if you notice your mower getting unusually hot or shutting down mid-task.

Some typical causes of overheating include:

• Blocked or dirty air filter: Restricts airflow, leading to an overworked engine.
• Low or old engine oil: Fails to lubricate internal components, causing friction.
• Overuse in hot weather: Mowing during peak sunlight can strain the engine.
• Dirty engine fins: Prevent heat from dispersing, which increases internal temperature.

Periodic inspections and cleaning by a professional can reduce overheating risks and extend the life of your equipment.

Noticing smoke coming from your lawn mower can be concerning, especially if you’re unsure what's causing it. Whether it’s white, blue or black, smoke clearly indicates that something isn’t working as it should. It’s your mower’s way of signalling that attention is needed.

In most cases, this is due to:

• Oil spillage: Spilled oil onto the engine during a refill can cause temporary smoke.
• Oil overfill: Too much oil can enter the combustion chamber.
• Worn piston rings or seals: Allow the oil to burn with fuel, creating visible smoke.
• Clogged air filter: This can result in improper fuel-air mix and incomplete combustion.

While some causes are minor and easily fixed, persistent smoke should be assessed by a lawn mower repair technician to avoid engine damage.

A patchy or uneven lawn after mowing clearly indicates something’s not quite right. While blunt blades are often blamed, they’re not always the root cause.

Additional causes of uneven cuts include:

• Unbalanced or damaged blades
• Uneven tyre pressure
• The deck height was set incorrectly
• Bent mower deck or axles

If your lawn is starting to resemble a checkerboard, it may be time for a professional tune-up to recalibrate your mower’s settings and restore uniformity.

Fuel leaks aren't just a nuisance—they're a fire risk. Spotting a puddle under your mower or smelling petrol means something’s gone wrong internally.

Here’s where leaks often originate:

• Cracked or brittle fuel lines
• Loose fuel tank caps or gaskets
• Worn carburettor seals
• Ageing fuel tanks with hairline splits

To avoid hazardous outcomes, shut off the machine immediately and do not use it again until a trained technician can diagnose and repair the source.

A bit of vibration is normal while mowing, but when your mower starts to shake noticeably—or your hands feel numb after a session—it’s a clear sign that something’s off. Excessive vibration isn’t just uncomfortable; it can indicate internal problems that may worsen if ignored.

Common culprits behind heavy vibration include:

• Loose or missing fasteners
• Unbalanced or bent blades
• Damaged spindle or crankshaft

Unchecked vibrations can lead to further component damage, so it's essential to have the machine serviced as soon as unusual movement is noticed.

Charging problems are an increasing concern for owners of electric or battery-powered mowers. A mower that runs out of juice within minutes isn’t just frustrating—it’s usually a symptom of deeper issues.

Typical causes include:

• Ageing or degraded batteries
• Loose electrical connections
• Defective chargers
• Improper storage over winter months

Batteries should be charged fully before storage and kept in a cool, dry place to ensure longevity. If problems persist, replacing the battery or checking the electrical system may be necessary.

Major faults don’t cause many common mower problems—they result from skipped maintenance. Over time, neglecting basic care can wear down your mower, reduce its performance and lead to costly repairs or early replacement.

Mistakes to avoid:

• Not changing the oil regularly
• Neglecting to sharpen or replace blades
• Storing fuel in the tank for long periods
• Ignoring the build-up of grass or debris under the deck

To keep your mower running smoothly, it’s wise to book seasonal servicing with a lawn mower repair professional—especially before and after the mowing season.

Regular maintenance is key to keeping your lawn mower running smoothly and extending its lifespan. At Diamond Service Centre, we focus on comprehensive lawn mower servicing and repairs in Lismore and the surrounding areas. Our experienced technicians are equipped to handle various issues, ensuring your equipment operates efficiently when you need it most.

Don't let mower problems disrupt your lawn care routine. Contact us today to schedule a service or repair. Our friendly team is ready to assist you with all your lawn mower needs.​