If your mower refuses to start, a systematic check of a few key components will usually identify the culprit. Knowing how to start a lawn mower correctly is the first step to a healthy, green yard and can save you a lot of frustration. This guide will walk you through the process for all common mower types, from simple push mowers to riding tractors, and help you troubleshoot when things don’t go as planned.
How To Start A Lawn Mower
Before you pull the starter cord or turn the key, you need to prepare the mower and understand its basic controls. A little preparation prevents damage and makes starting much easier.
Safety First: Essential Precautions
Always prioritize safety. A moment of carelessness can lead to serious injury.
- Clear the mowing area of sticks, stones, toys, and other debris.
- Check that all safety guards and shields are in place, especially the discharge chute or bag.
- Wear sturdy closed-toe shoes and eye protection.
- Never refuel a hot engine. Wait for it to cool completely to avoid fire.
- Start and run the mower outdoors only, never in a garage or shed, to avoid carbon monoxide buildup.
Pre-Start Checklist
Go through this quick list every time you plan to mow. It takes just a minute.
- Check the Oil: Use the dipstick to ensure the oil level is between the marks. Too little or too much oil can prevent starting.
- Check the Fuel: Make sure you have fresh gasoline. Gas older than 30 days can degrade and cause starting issues.
- Inspect the Air Filter: A dirty air filter chokes the engine. Tap it clean or replace it if it’s very dirty.
- Engage the Blades: For riding mowers, ensure the blade engagement lever or switch is in the “Off” position before starting.
- Prime the Engine (if equipped): Press the primer bulb 3-5 times to draw fuel into the carburetor.
Starting A Push Mower With A Recoil Starter
This is the most common type of lawn mower. The starting procedure is straightforward once you get the hang of it.
- Set the engine speed control to “Fast” or the choke symbol if the engine is cold.
- If your mower has a primer bulb, press it several times until you see fuel in the bulb.
- Locate the safety handle on the mower’s handlebar. You must hold this down the entire time the engine is running.
- Place one foot firmly on the mower’s deck for stability (not near the discharge chute).
- Grip the starter cord handle firmly. Pull the cord smoothly and quickly until you feel resistance, then give it a strong, full pull. Do not yank it or let the cord snap back violently.
- If it doesn’t start on the first or second pull, move the throttle to the “Fast” position and try again. Once started, you can adjust the throttle to your desired mowing speed.
Starting A Self-Propelled Or Electric Start Mower
These mowers follow the same basic principles but with a conveniant twist.
Self-Propelled Models
The starting procedure is identical to a standard push mower. The self-propelled drive system is typically engaged by a lever or button on the handlebar after the engine is running.
Electric Start (Key or Button) Models
- Complete the pre-start checklist and ensure the mower is plugged into its outdoor extension cord if it’s a plug-in model.
- For battery-powered electric start, insert and turn the key or simply press the start button while holding the safety handle.
- For plug-in electric start, ensure the cord is connected, then turn the key or press the button.
- If the engine turns over but doesn’t start, refer to the troubleshooting section below.
Starting A Riding Lawn Mower
Riding mowers have more steps, but they are logical and easy to remember.
- Get seated and ensure the parking brake is firmly engaged.
- Set the blade engagement lever to “Off” or “Disengaged.”
- Move the throttle/choke control to the “Choke” position for a cold start.
- If your model has a fuel shut-off valve, make sure it is in the “On” position.
- Turn the ignition key to the “Start” position. Release the key as soon as the engine starts; it will spring back to the “Run” position.
- Once the engine runs smoothly, you can adjust the choke to the “Run” position and release the parking brake.
Step-By-Step Troubleshooting: When Your Mower Won’t Start
If you’ve followed the steps and your mower still won’t start, don’t panic. Work through this diagnostic list in order.
Check The Obvious First
- Is there fresh fuel in the tank? Old gas is the number one cause of starting problems.
- Is the spark plug wire securely attached? It’s the thick wire leading to the top of the engine.
- Is the safety handle fully engaged? Some mowers have a sensor that must be depressed.
- For riding mowers, are you fully seated? Is the parking brake on? Is the blade engagement off?
Diagnosing A No-Pull (Recoil Starter Issues)
If the starter cord is stuck or won’t pull, the engine or starter mechanism may be jammed.
- Disconnect the spark plug wire for safety.
- Check under the mower deck for a wrapped cord or packed grass blocking the blade.
- Try manually turning the engine blade (with a wrench, if accessible) to free it. If it’s completely seized, professional repair is likely needed.
Diagnosing A Weak Pull Or No Spark
The cord pulls but the engine doesn’t even sputter.
- Spark Plug: Remove the spark plug, reconnect its wire, and rest the metal base against the engine block. Pull the starter cord. You should see a blue spark. If not, replace the plug.
- Fuel System: Smell the gas cap. If the gasoline smells sour or varnish-like, drain and replace it. Check that fuel is reaching the carburetor.
- Carburetor: A gummed-up carburetor from old fuel is a common issue. It may need cleaning or rebuilding.
Seasonal Starting Tips
Proper storage is the key to easy starting next season.
Preparing For Winter Storage
- Add a fuel stabilizer to a full tank of gas and run the mower for 5 minutes to circulate it through the system. This prevents fuel breakdown and carburetor issues.
- Disconnect the spark plug and drain the old engine oil. Refill with fresh oil of the recommended type.
- Clean the mower deck thoroughly to prevent rust.
- Store the mower in a dry, covered place.
First Start Of The Spring Season
- Check and change the oil if you didn’t in the fall.
- Install a new spark plug and air filter. These are inexpensive and make a big difference.
- Check that the fuel you left in the tank over winter is still good. If in doubt, siphon it out and add fresh gasoline.
- Follow the standard starting procedure. It may take a few extra pulls to get fuel flowing.
Frequently Asked Questions
How many times should you prime a lawn mower?
Typically, you should press the primer bulb 3 to 5 times for a cold engine. If the engine is warm, one or two primes is often enough, or sometimes none at all. Over-priming can flood the engine.
Why does my lawn mower start then die?
This often points to a fuel delivery problem. Common causes include a dirty carburetor, a clogged fuel filter, a faulty fuel cap vent, or old gasoline. The engine uses the fuel in the carburetor bowl to start but then starves.
What is the correct starting procedure for a cold engine?
For a cold engine, set the throttle or choke control to the “Choke” position (often a symbol of a closed butterfly). Prime it if equipped. Then pull the cord or turn the key. Once it starts and runs roughly, gradually move the choke to “Run” over 30 seconds.
Can bad gas cause a mower not to start?
Yes, stale gasoline is the most frequent cause of starting failure. Gasoline begins to oxidize and form varnish in as little as 30 days, which clogs the carburetor’s tiny jets and passages. Always use fresh fuel.
How do I start a lawn mower that has been sitting for a year?
First, drain all the old fuel from the tank and carburetor. Add fresh gasoline. Change the engine oil and replace the spark plug and air filter. Check for rodent nests near the engine. Then, follow the standard starting steps. It may require several pulls to draw new fuel into the system.