Devin Jacobs
Did you know many lawnmower mishaps can be traced to basic maintenance oversights that most people overlook? These common culprits often lead to unnecessary frustration, especially when you’re eager to tackle your lawn. Fortunately, many problems are easy to fix and can be addressed with just a little know-how. In this article, we’ll walk you through 15 easy fixes for common lawn mower starting problems, arming you with the knowledge to tackle these issues head-on.
Check the Fuel Level
Not having enough fuel is a typical problem that can prevent your engine from starting. Before anything else, take a moment to check if there’s gas in the tank. If you find it empty or the fuel is older than 30 days, it’s time to refill with fresh gas, as old fuels can degrade.
Inspect the Spark Plug
Locate the spark plug, usually found on the side or front of the engine. Remove it and check for any signs of wear or buildup. If it looks dirty, clean it with a wire brush or replace it entirely if it’s severely worn out. Make sure it’s tightly connected when you reinstall it.
Prime the Engine
Some lawnmowers, especially older models, require you to manually prime the engine before starting. Check if your mower has a primer bulb, typically a small rubber button on the engine’s side. Press it a few times to draw fuel into the carburetor. Don’t over-prime to avoid flooding the engine with fuel.
Examine the Carburetor
The carburetor plays a significant role in mixing air and fuel for combustion. If clogged or dirty, your mower may struggle to start or run poorly. Inspect the carburetor for debris or corrosion by removing the air filter. Use a carburetor cleaner and ensure all passages are clear.
Clean or Replace the Air Filter
A clogged air filter limits the engine’s airflow, making it difficult for your mower to start. Pop open the air filter cover, pull it out, and check its condition. If it’s clogged with dirt and debris, you can clean it with soap and water or replace it altogether.
Check for Fuel Blockages
Sometimes, fuel can’t reach the engine due to blockages in the fuel line or filter. If you suspect this might be an issue, inspect these components carefully. You can gently tap on the carburetor to encourage fuel flow. Always refer to your owner’s manual for specific instructions on locating these parts to ensure functionality.
Test the Battery
If you own an electric or riding mower with a battery, checking its charge is essential. A blocked air filter, due to age or corrosion on terminals, hampers the engine’s ability to draw in air effectively. Use a multimeter to test battery voltage; if it’s low, consider recharging or replacing it altogether.
Assess Oil Levels
Just like cars, lawnmowers require oil for smooth operation. Low oil levels can prevent starting and damage internal components over time. Check your oil dipstick; change it immediately if it’s low or appears contaminated (like milky white). High-quality oil suited for your mower model will ensure optimal performance and longevity.
Look at Safety Features
Modern lawnmowers have safety features that prevent them from starting under certain conditions—such as when the blade is engaged or controls are not set correctly. Double-check that all safety mechanisms are disengaged before attempting to start again. Consult your owner’s manual for guidance on proper control settings.
Clear Debris from Underneath
Grass clippings and debris can accumulate under your mower deck and cause mechanical issues like blocked blades or stuck starter ropes. Turn off and tip your mower safely onto its side (make sure it’s cool first!) and clear out any buildup using a trowel or similar tool. A clean deck will help with starting.
Check Ignition System
If everything else seems fine but your mower still won’t start, there may be an issue with the ignition system itself—this includes components like ignition coils and wiring connections that may have come loose over time. Inspect these parts visually for any signs of wear or damage; replacing faulty ignition components can restore functionality.
Look at Compression Levels
Low compression levels in your engine may indicate more serious internal problems like worn piston rings or valves not sealing properly—issues that could prevent starting altogether. While testing compression requires specific tools like a compression gauge, knowing how to do this can save you time diagnosing deeper issues.
Examine the Fuel Cap Vent
The fuel cap on your mower has a small vent that allows air to flow into the gas tank. Without proper venting, a vacuum can form in the tank, preventing fuel from flowing into the engine. Test the vent by loosening the fuel cap and trying to start the mower again.
Confirm the Flywheel Key is Intact
The flywheel key, a small metal part that helps the engine maintain the correct timing between the piston and the spark plug, should be constantly inspected. If the flywheel key shears off—often due to hitting a hard object like a rock or stump—the timing will be off, and the mower won’t start.
Replace the Starter Rope
If your mower’s starter rope feels difficult to pull or gets stuck halfway, it could be frayed or damaged. Over time, wear and tear on the starter rope can make it harder to start the engine. Examine the cord for any frays or breakages. If it looks worn out, replace it with a new one.