How to Jump Start a Lawn Mower

Different methods to get your mower running again

Co-authored by Grant Wallace

Last Updated: May 10, 2024 References

Riding lawn mowers and even some high-end push mowers depend on battery power to keep the engine running. Whether you’re about to break out your mower after a long winter or just forgot to shut off the ignition, a drained battery can stop you in your tracks. However, you can easily recharge it with a working car battery. You could also use a battery charger for a slower, more gradual fix. As long as you’re cautious and take all possible safety precautions, you can get your lawn mower operational again in no time.

Method 1

Method 1 of 3:

Accessing the Mower’s Battery

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1
Move the mower onto a hard, level surface. Select a spot with plenty of room for you to move around the mower. Try rolling the mower into your driveway, for instance, or onto pavement. Make sure you’re away from moving vehicles.^{[1]
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- If you’re using a battery charger, select a spot near an electrical outlet. For instance, it’s usually best to use a charger inside your garage.
2
Put on a pair of work gloves and safety glasses. Get a quality pair of work gloves, such as rubber-coated or mechanic’s gloves. The gloves can help insulate you from electrical shock, heat, and battery acid. Put on fitting safety glasses as well to shield your eyes from any sparks that might shoot up from the battery. Remove any sort of metal jewelry that could potentially come into contact with the battery cables.^{[2]
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- Wear the protective gear at all times when working with batteries.
- Wear long pants, a long-sleeved shirt, and closed-toe shoes as well for additional protection.
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3
Open the compartment containing the battery. On a riding lawn mower, the battery is either under the hood or the seat. Check the seat first by pushing it up toward the front of the lawnmower. If the battery isn’t in the compartment underneath it, pull open the front hood. Look for a small lever near the hood that can be used to pop it open.^{[3]
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- If you’re unsure where the battery is or can’t figure out how to open the battery compartment, check your owner’s manual. Lawn mowers all open a little differently from one another, so use the manual for more specific instructions.
- If you own a push mower, you won’t have to look too hard. It is either in a box near the handles, under the cover on the engine compartment, or next to it in a separate slot.
4
Shut off the mower’s engine before attempting to charge it. Double-check that the ignition is actually off. Follow the instructions in your owner’s manual covering how you normally start the mower. For instance, in a riding mower, turn the ignition lever near the steering wheel to the left. Then, pull the blade control lever on the steering wheel down to deactivate the blades.^{[4]
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- The ignition has to be off in order to prevent electrical shock or battery damage. It’s easy to forget that the ignition was left on and then end up with your mower suddenly roaring to life at the wrong time.
5
Clean the battery terminals with a wire brush if they look corroded. Battery corrosion looks like a white or green crust. It’s unpleasant, but it’s also acidic, so put on rubber gloves and safety glasses before doing anything else. Then, mix 1 tablespoon (14.40 g) of baking soda into 1 cup (240 mL) of warm water. Scrub off all of the corrosion so the battery is safe to use.^{[5]
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- If you don’t see any corrosion, you won’t have to clean the battery. However, check it for corrosion at least twice per year, particularly when the battery hasn’t been used in a while or after it has lost its charge.
- If the battery is highly corroded or has acid leaking out of it, you’re better off replacing it. Old batteries are more prone to corrosion, so it could be a sign that your battery is no longer a great choice for your mower anyway.
- Corrosion can cause a battery to no longer work. After clearing away corrosion, test your mower again to see if it starts. If it doesn’t, try charging it.
6
Check the voltage on the battery to see if it’s 12V or 6V. The battery will have a big sticker on one side with the voltage printed on it. Most mowers use 12V batteries, but it doesn’t hurt to make sure yours does. For safety reasons, a 6V battery cannot be jump-started with a 12V car battery. Use a 6V charger instead to prevent the battery from overheating and suffering permanent damage.^{[6]
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- Lawn mowers made before 1980 could use a 6V. Use a 6V battery charger to power these batteries.
- Voltage is a power measurement that tells you how much power is needed to operate the mower’s engine. You should always use a charger with the same voltage rating as the battery. Jumpstart it with another battery only if they both have the same voltage.

Method 2

Method 2 of 3:

Using Jumper Cables and a Car Battery

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1
Park your car near the lawn mower and shut off the engine. Pull the car up so the engine compartment is right next to or facing the lawn mower’s battery. Make sure the car is also on level, stable ground. You should also have plenty of room to stretch jumper cables from the lawn mower to the car.^{[7]
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- Engage the parking brake so the car has no chance of rolling away while you’re using it.
- Note that jump-starting only works on 12V batteries. Most mowers, including push mowers, use 12V batteries.
- Jump starting a riding lawnmower is easy, but you may have trouble doing this for some push mowers due to the placement of the battery. The terminals can be hard to reach. Instead, remove the battery and connect it to a charger.
2
Open the engine compartment hood on your car. Locate the hood release lever on your car. Yours may have a lever inside the car on the driver’s side. If it isn’t there, check near the grill on the car’s front end. Press the lever until you hear the hood pop, then raise it to keep it open.^{[8]
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- If you’re unsure how to open the hood, check the owner’s manual. It varies from car to car. For instance, some have push buttons, while others have levers you have to pull.
- Make sure the engine is cold before opening the hood. If you just turned it on to park it, it will be fine. However, if you drove it recently, give it 30 minutes to cool down.
3
Connect a red jumper cable to the positive mower, then car terminal. Jumper cables have sets of red and black clamps, and one set is used for each battery. Separate the clamps, then take one end of the red cable to the mower battery. The battery will have metal terminals on top of it. Hook the cable to the one marked “+.” Secure the other end to the matching terminal on the car’s battery.^{[9]
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- If you have an electric vehicle, make sure its charger isn’t plugged into the wall before you attempt to clamp any cables to the battery.
- Once you connect the first clamp to the battery, make sure the clamps don’t touch any other metal. It could cause permanent damage to the battery.
4
Secure the black jumper cable to your car’s negative battery terminal. Start with the terminal marked “-” on the car. Hook the clamp to it, making sure it doesn’t bump the clamp on the positive terminal. Check that both clamps are secure on the terminal and separate from any metal components surrounding the battery. Don’t hook the opposite end of the jumper cable to anything yet.^{[10]
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- While connecting both ends of the black jumper cable to the batteries still works, it increases the risk of an explosion. It’s one of the most common mistakes people make when jump-starting a battery.
5
Place the remaining black clamp on a bare piece of metal. The last black clamp is used to prevent any accidents with the battery. Find a good spot away from the fuel tanks and batteries in both vehicles. One good spot is the hitch on the back of the mower. You could also connect it to a part of the car’s frame, such as an exposed bolt near the engine.^{[11]
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- The electric current could potentially ignite gasses around the battery, so it’s very important that you attach the clamps with caution. If you take your time, you can avoid any risk of an explosion.
6
Start the car’s engine to direct a charge to the mower. Climb into the driver’s seat and put the start key in the ignition. Use it to start the motor. Keep the mower turned off while you do this.
- Double-check that the mower is off so that you don't overload its battery upon starting your car.
7
Turn on the mower to start its engine. Leave the car running while you walk over to the mower. Be careful to avoid bumping into the jumper cables. Once you turn the mower’s ignition switch, you should hear the engine rumble back to life. The battery can take about 30 minutes to fully charge, so leave it connected to the car battery for at least 5 minutes.^{[12]
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- Expect to see a few sparks when you first start the engines. It’s normal and won’t damage the batteries. However, if you see a ton of sparks and they don’t stop right away, shut off both vehicles.
- If the mower doesn’t start, turn off both vehicles and look for other problems. Make sure the jumper cables are connected, for instance, and that the mower has plenty of gas.
8
Disconnect the jumper cables in reverse order, starting with the black clamps. The grounding clamp comes first. Remove it, then set it aside in a spot where it won’t come into contact with any other piece of metal. Remove the other black clamp from the car’s battery. Then, detach the red clamp from the car, followed by the red one on the mower’s battery. After disconnecting the cables, drive your mower around for up to 30 minutes to ensure its battery stays charged.^{[13]
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- You don’t have to shut off either vehicle before removing the cables. It’s best to at least leave the lawn mower running so its battery continues to charge.
- Keep in mind that the clamps can still cause a short while they are connected to a battery. Once they have all been disconnected, they can safely touch metal surfaces again.
- The mower’s battery will charge while you’re using it. Consider hooking it up to a battery charger afterward to ensure it finishes charging.

Method 3

Method 3 of 3:

Connecting a Battery Charger

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1
Choose a 10-amp charger matching your lawn mower’s battery. Just like how batteries come in a wide range of sizes, there are many different types of chargers for them. The 10-amp version is small, compact, and not too strong for a lawn mower battery. In addition, make sure the charger matches the battery’s voltage. Most mower batteries are 12V, but you will need a charger with a 6V setting if you have a 6V battery.^{[14]
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- Amps are a way to measure the strength of an electrical current. A strong current can overload your battery, destroying it.
- If you’re able to, get a charger with an automatic shut-off feature. It will help protect your battery in case you forget to disconnect it right when it finishes working.
2
Clamp the red cable to the mower’s positive battery terminal. Locate the pair of metal terminals on top of the battery. One of these terminals will have a red cap or have a label like a “+” sign. Fit the charger’s clamp onto the terminal, then give it a firm shake to ensure it’s firmly in place.^{[15]
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- Leave the battery charger unplugged while attaching the charger cables.
- To protect your battery and reduce the risk of electrical shock, double-check that the charger cable is attached to the correct terminal before continuing.
3
Place the black cable clamp onto the negative battery terminal. The negative terminal will be right next to the positive one. It will have a black cap or a label, such as a “-” sign. Secure it onto the terminal, making sure it won’t fall off when you walk away from it.^{[16]
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- Battery chargers tend to have an auto-start feature, meaning that they won’t work until you have finished securing the clamps properly. You won’t end up with sparks or a possible short if they happen to come into contact with a metal object.
4
Plug the charger into the wall and leave it for 1 hour. Once the battery is plugged in, electricity will be able to flow to the lawn mower. It takes a while to charge, so be patient with it. You can leave the lawn mower alone while the battery charges.^{[17]
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- If you’re using a low-amp setting, you might have to charge the battery for longer than 1 hour. Check the charger’s display for a light or a meter monitoring the battery’s charge.
- Some chargers have an automatic shut-off feature. The charger will stop when the battery is full, and this will be indicated by a light on the charger’s screen.
5
Disconnect the charger before starting the mower. Unplug the power cord from the wall outlet first. Then, remove the black cable clamped to the battery. Finally, detach the red clamp. Once the charging cables are gone, you can start your lawn mower to see if it works again.^{[18]
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- To prevent overcharging the battery, remove the charger as soon as the battery finishes charging. Otherwise, the charger could cause damage to the battery.
- After disconnecting the charger, store it in a safe, moisture-free spot until you need it again. The clamps can touch without causing damage to the charger.
- If you suspect your mower has more problems beyond a dead battery, consider bringing it to a repair shop for an in-depth inspection.

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How do you move a riding lawn mower?

Grant Wallace
Landscaper
Grant Wallace is a Landscaper and Owner of Grantlanta Lawn in Atlanta, Georgia. With over seven years of experience, he specializes in lawn maintenance and landscape installation. In 2012, he earned his BA from the University of West Georgia. Grant has been profiled in Shoutout Atlanta, Canvas Rebel, and Voyage ATL.

Grant Wallace

Landscaper

Expert Answer

Switch the mower to a neutral setting (or at least make sure the brake levers are off)—that way, you can roll it around. If you need to transport it somewhere else, you can either use a chain apparatus to pull it into a trailer or push it manually (assuming the trailer has a ramp). You could also call the repair shop and see if they can come to your place and fix the mower.

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Tips

To make jump starting even safer, remove the battery from the mower first. If you wish to do this, use a socket wrench to loosen the nuts on the terminals.^{[19]
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If a battery doesn’t work even after you charge it, it may just be broken. Leaks, bloating, and slow engine startup are a few warning signs as well.

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Take the battery out and store it separately from the mower when you don't plan on using it for an extended period of time. That way, there's less risk of corrosion forming.

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Warnings

Attempting to charge a battery can cause electrical damage or an explosion. Be very careful to attach the clamps in the correct order without letting them touch other pieces of metal.

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To reduce the risk of electrical shock and burns, wear safety glasses and work gloves at all times.

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