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Toro Lawn Mower Won’t Stay Running

If your Toro lawn mower stops working after you start it, you need to take some time out to have a look at the machine and pinpoint possible causes. In many cases, you can solve the problem on your own without visiting a mechanic.

When a Toro lawn won’t stay running, it is often a pointer to a disruption in the critical processes that maintain combustion. There could be some problem with the machine’s gas intake, spark plug, or airflow. A combination of all or some of these factors can keep your mower from running smoothly.

The rest of the article will take a closer look at some of these reasons why a Toro lawn mower won’t stay running and when you should call in a service technician.

Toro Lawn Mower Starts And Stops

A frequent issue with Toro lawn mowers starting and then stopping is due to stale or contaminated fuel. Old or impure fuel can prevent the mower from running smoothly. To address this, drain the old fuel from the tank and replace it with fresh gasoline. Ensure you use fuel that’s less than 30 days old for optimal performance.

A faulty spark plug can also cause a Toro lawn mower to start and then stop. The spark plug is responsible for igniting the fuel-air mixture in the engine. If it’s worn out or fouled, it might not provide a consistent spark. Inspect the spark plug for signs of wear, corrosion, or deposits. If any irregularities are found, replace the spark plug to ensure a consistent ignition and smooth mower operation.

Problems With the Gas Line

Did you expose your Toro lawn mower to water? There may be water in the engine, preventing it from running properly. It’s also possible that the water entered the engine through the gas chamber. It’s easy to pour gas that has already mixed with water into the engine unknowingly.

Other ways through which moisture can enter the mower’s engine include a poorly-fitted gas cap or condensation in the gas tank.

If moisture in the engine is the problem, the mower will run for a while before it sputters and dies. In this scenario, the best thing to do is to drain the gas in the tank and refill it with fresh, non-contaminated gas.

Another problem common with the gas line on a mower is a clogged fuel filter. Debris in the bottom of the gas tank can get lodged between the tank and the carburetor, starving the engine of the right quantity of gas it needs to stay running. You can solve this problem by changing the fuel filter.

Changing the air filter is also beneficial when dealing with moisture in the engine. To ensure the gas line is clean, rinse out the tank, refill it, and dispose of any drained fuel.

Problems With the Spark Plug

A bad spark plug can make it difficult for a mower to start, but it can also make it harder for the engine to stay running. Some spark plug problems won’t surface until the mower has run for several minutes. If it’s been a while since you looked at the spark plug in the mower, take it out.

Inspect it to see if the white housing is chipped or cracked. You should also look at the rounded tip on the center electrode (the small metal poking out of the casing) for damage.

If the spark plug looks damaged in any way, you have to get a new one as it can’t be repaired. If the plug is fine, but you find the firing end packed with soot, you can clean it off with a stiff wire brush. You should also check the gap between the center electrode and the grounding one (the curved metal at the top). Reset the gap by slightly bending it inwards or outwards to maintain the optimal gap.

Air Flow Problems

Gas isn’t the only thing your mower needs to run. Without air, the gas in the tank won’t count for much. However, the air has to be in the right balance. Too much or too little and the engine won’t run consistently.

If the air filter in your Toro lawn mower is dirty, it will almost certainly block or limit the air flowing into the engine. Clean the dirty filter or consider replacing it completely. The gas tank cap also comes with a vent on top, which provides the pressure needed to push fuel through the lines.

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The pressure will be distorted if the hole is blocked. A bent gas cap or one with a seal that’s already damaged will also have the same effect. With the inadequate pressure, the mower will struggle to continue running while in use, tripping off when the supply of gasoline is no longer enough.

You should also take a look at the mounting bolts for your carburetor to ensure that they are tight. If they are loose, the carburetor will suck up too much air.

Carburetor Problems

The carburetor is responsible for ensuring the perfect mix of fuel and air to ensure your mower is running smoothly. Inside a carburetor, you’ll find many small parts working together, including needle valves, floats, springs, spray jets, etc. These can get clogged or damaged with persistent use.

Cleaning or replacing a carburetor is easy if you are used to mechanical DIYs. However, if you aren’t, it is a good idea to allow a professional to do the job.

How to Keep the Mower From Stalling in the Future

When you have your lawn mower up and running again, you’d want to avoid a repeat of the problem or at least keep the occurrence to the barest minimum. Here’s what you should do.

Pay Attention to the Manufacturers

Your owner’s manual comes with instructions on how to take care of your lawn mower. These are tips that can keep your machine running optimally for its lifetime. Pay attention to what you find in the manual and stick to as many of them as possible.

Don’t Leave Gas in the Tank

Old gasoline getting into the engine can lead to damage. The chemical reaction that forms when you leave the gas in the tank at the end of a mowing season will make the machine difficult to start if you go right back to trying to use it when the next season rolls around. Even when it starts, it may be hard to keep it running. So, keep the tank empty when you know that the machine could go unused for weeks.

Monitor the Oil

The oil in the mower should be at the recommended level at all times, but don’t forget to drain it when it is old or when it gets contaminated. Your owner’s manual should also be your guide for the type of oil to use.

Clean the Underside

If grass gets caked in the undercarriage of your mower, it can clog its discharge chute. You can get rid of the grass (and any other dirt) with a wire brush and then spray any remnants with a hose. Before you get started on the cleaning, however, you should turn off the mower and disconnect the spark plug to avoid any accidents.

Book a Professional Maintenance Session

Taking your mower for professional maintenance before the start of a mowing season is a great way to ensure that it doesn’t disappoint. Most maintenance shops will run a basic diagnosis to pinpoint possible issues and get them sorted. 

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Some of the things we’ve covered above, such as replacing spark plugs and air filters or servicing a carburetor will be done in a typical maintenance session. You may also get the blades of the lawn mower sharpened for an extra fee or as a part of the entire package.

The maintenance cost is typically around $100—a small price to pay when compared to the inconvenience that comes with having your lawn mower stopping a few minutes after you start using it.

Final Thoughts

If you have a Toro lawn mower that won’t stay running, the problem is almost often gas, spark plugs, or air-related. By ensuring you are using uncontaminated gas, and keeping the air filters clean, and using working spark plugs, you can get the mower back to normal.

After troubleshooting in these areas, if you still can’t get the machine working correctly, it is time to call in a professional that has experience repairing mowers like yours.

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