Lawn Mower Engine Cooling Times Explained


You have spent all afternoon cutting the grass and giving your front yard that pristine look that your neighbors have come to envy. You go to take care of the backyard when your lawn mower decides it is time for a break, and it overheats. I have customers contact me about this all of the time.

How long should you expect to wait until you are up and running? The answer can vary depending on a few different variables.

Engine cooling times vary depending on the engine being air or liquid-cooled, the size of the engine, the age of the oil, and external variables like the temperature outside or thickness of the grass. Smaller, cleaner, air-cooled engines will cool faster than their larger, dirtier counterparts. 

All lawn mowers are constructed differently and, therefore, will have differing engine cool down times. Keep reading to learn how to maintain a clean, strong engine that maximizes engine power while keeping cool down times reasonable. 

lawn mower engine cooling times

This post may include affiliate links. Purchases made through these links may provide a commission for us, at no extra cost to you. As an Amazon Associate we earn from qualifying purchases.

Why Does my Lawn Mower Overheat?

While researching ways to improve the cool down time for your lawn mower’s engine, it is vital to try and learn what causes the engine to overheat in the first place. Many factors can cause engines to overheat and malfunction. Some of these causes are:

  • Metal expansion
  • Low or old oil
  • Dirty engine
  • Damp and thick grass 
  • Old components

As engines run, their components heat up, and the metal that they are made of expands. This expansion can be overwhelming to the system, causing the engine to increase in temperature at a rate that the cooling system cannot keep up with. Therefore, it is vital to ensure that your engine is clean, has all the proper fuel, and that its components are not overused, run-down, or old.

Clogged air pathways are often a common cause of overheating as well. Large pieces of debris can be lodged in parts of the engine block or even outside of it and block important vents that work as entrance or exit points for air. Air is important, not only for the reactions needed to make an engine work properly but to keep the engine components cool enough to function at all. 

You will know your lawn mower is overheating if you see smoke or steam rise from the engine cap, the sounds of the engine change to chugging-like noises, or if the lawn mower shuts down completely. 

Read more about overheating problems with our article, “7 Things That Can Cause a Lawn Mower to Overheat“.

How Do I Cool Down my Lawn Mower?

There is not a single remedy to cool down all lawn mowers. Every mower is different because they use different engines, different cooling systems and are used differently by their owners. While you may keep your lawn short and cut it several times a week, others may only cut their grass once a month. 

This means they will be trimming thicker grass than you, causing their lawn mower to exert more energy and the engine to run harder and hotter. There are several ways to ensure your lawn mower cools down in a reasonable amount of time:

  • Let the engine idle
  • Change the oil
  • Keep the engine clean
  • Follow your unit’s instructions
  • Research your mower’s cooling system
  • Pay attention to external variables

Let The Engine Idle

While it is the simplest solution to a complex problem, letting your lawn mower’s engine idle after using it can help the engine cool down. Idling is a twofold solution to overheating. Firstly, it allows the oil to flow through the engine and disperse the heat from one part of the engine across the whole engine, allowing it to cool down evenly and faster. 

The second reason idling helps your engine cool down is because it allows the fans in air cooling systems to force air across the surface of your engine and decrease the external temperature. 

Typically, a ten-to-thirty second idling period is enough to aid in engine cool down. Letting your motor idle too long can cause the oil and engine to heat further, causing a slower cool down time. 

Idling has several definitions depending on who you ask or which lawn mower manual you read. Whether you let your lawn mower sit stationary after each use before turning the engine off or you decrease the power or speed during your last few minutes of use, both of these can be considered idling. 

Check and Change the Oil

When a lawn mower’s engine is running, certain parts will heat up faster than others. Many mower manuals will advise you to leave your mower running at an idle after each use. This is so that the oil can do its job in helping disperse the heat of one particular part or section of the engine and evenly distribute the heat across the entirety of the engine. This process is called temperature stabilization. 

When checking your oil, ensure the engine is off for a substantial period so that you do not burn yourself. Use a dipstick or an oil pump to check the levels and color of the oil. If your oil is dark and grainy, it is too old and can do more harm than good by sticking to engine components and burning, causing more heat. 

If your oil needs to be changed, check your mower’s manual to see what type of oil it takes. After purchasing the correct oil, follow these steps:

  • Run the engine for about fifteen minutes to move the oil through the engine 
  • Turn off the engine and disconnect the spark plug wire
  • Ensure the gas cap is tightened or remove the gas tank if needed
  • Remove the oil drain plug and drain the old oil, ensuring all oil is removed
  • Replace the oil drain plug and use a funnel to add the new, correct oil
  • Replace any parts that were removed and run the engine for a few minutes

If your oil is old and dirty, this could have been the cause of your engine overheating or extending the engine cool down time. After your next use, pay attention to see if your lawn mower cools down at a faster rate. 

Not changing engine oil regularly can cause extensive engine damage. Read more about it in our article, “What If You Don’t Change Oil in Your Mower“.

Keep The Engine Clean

Keeping the inside and the outside of your engine clean is of utmost importance. While you may not have the expertise to ensure the inside of your engine is clear of debris, keeping the external portion of your engine and lawn mower clean is easy and vital to swift cool down times.

If a build-up of dirt, grime, and grass occurs on top of your lawn mower, it blocks the air filtration and cooling systems. If the air cannot be filtered and the air cooling system cannot run properly, there is no possible way for your engine to cool down. Not only is this bad for your engine, but it is also dangerous. Dried grass can be incredibly flammable, and added to a conductor of heat like an engine is a recipe for disaster.

Make sure that your chute is pointed in the proper direction. Your bag is securely fastened with no leaks, and clean off the debris that finds its way on to and into parts of the engine that you can see. 

How to Clean Your Lawn Mower for Best Performance

Follow Your Lawn Mower’s User Manual

Every engine is constructed differently. Every lawn mower runs differently. What may work for some lawn mowers will not work for others. There are no coverall answers when it comes to engine cooling and maintenance. 

Following your lawn mower’s user manual will protect you from voiding any warranties that you may have, as well as safeguard your engine against any problems that may arise from quick fixes or do-it-yourself solutions.

While you may save money in the short term by rigging your custom cooling system or engine parts, you are damaging the integrity of your lawn mower and will most likely end up paying for a brand-new engine or an entirely new lawn mower.

If your engine is not cooling fast enough, check your lawn mower’s user manual first before turning to forums or blogs for answers. It may be something as simple as cleaning an air filter or running your lawn mower for a few extra minutes. 

Research Your Lawn Mower’s Cooling System

Depending on the size of your lawn mower and the type of engine it has, you will likely encounter two different cooling systems: air-cooled and liquid-cooled.

Air-cooling systems are by far the most common for non-industrial lawn mowers. Air-cooling systems will be found in many push and ride law mowers. Air-cooling systems use sets of fans that push air to cooling fins found inside of the engine. These fins keep the air in circulation throughout the engine and cool it down. 

If you have an air-cooling system, and it is probable that you do, keeping the oil clean, and the lawn mower and engine block clean are your best bets at ensuring that it is working properly. Debris and old oil can clog the cooling fins and restrict air circulation. 

Liquid cooling systems are much less common. These are typically found in large mowers with heavier engines. Liquid cooling systems are known to be much more effective than air cooling systems, but they are far more expensive and heavier. If your mower has a liquid cooling system, ensure that you are using the proper coolant and that coolant levels are correct. 

Understanding which type of cooling system is in your lawn mower lets you understand the proper steps to take to make sure your engine is cooling in the correct amount of time. 

Pay Attention to External Variables

It is just as important to note the specifications of your engine and its cooling system as it is to note things like air temperature, the thickness or moisture of the grass you are cutting, and debris that can be problematic if mowed over. 

Your mower’s engine is far more likely to overheat on a day that is 100 degrees than it is on a day that is only 75 degrees. Therefore, if you find yourself mowing in extreme heat, you should think about how hard you push your mower and for how long the engine can maintain that level of power. 

While you pay attention to those temperatures, the only thing your mower is doing is pushing through that lawn of yours. Again, if you cut your lawn regularly, your grass will be easier to cut. If your lawn is longer and thicker, the engine will have to work harder to compensate for the increase in power needed.

This is also true if there is excess moisture in the grass. Wet grass, like after a rainstorm, requires more power to cut through. The higher the power output, the harder the engine works and the hotter the engine gets. 

On top of the lawn you are cutting, you should always keep an eye out for debris like sticks or rocks. Mowing over these types of obstacles can not only damage the blades of your mower but can be sent through the chute with the grass and damage the internal structures of the mower and engine.

If engine components are damaged, your mower’s engine will not function correctly, and overheating will be one item on a very long list of problems. 

Keeping Your Mower Clean for Proper Cooling

Keeping a clean engine is a great way to make sure that your lawn mower can cool down properly. Taking proper precautions and understanding how to appropriately clean inside of your engine to the best of your understanding without expertise can help extend the life of your mower exponentially. 

Some steps to cleaning your lawn mower engine are:

  • Turn the engine off and unplug the spark plug wire
  • Remove the engine screen or cover by following the mower’s user manual
  • Use a brush and/or a mild washing soap to clean the cooling fins
  • Remove any large pieces of debris easily visible
  • Empty the fuel tank and refill with fresh fuel
  • Clean the undercarriage near the blades of any debris

You should avoid using compressed air or long brushes because they can push pieces of debris further into the engine and do more harm than their previous position. 

If you do not understand what you are looking at, use diagrams to identify the engine components you are attempting to clean. User manual are often handy in identifying where engine parts are located and what they are supposed to look like. It is better to ask questions and research than it is to take blind guesses at what you are touching. 

Remember to only proceed up to your comfort level. If you are not comfortable taking pieces of your lawn mower off or maneuvering around key engine parts or blades, check to see if maintenance is covered by your warranty or find a certified engine repair shop or mechanic that has expertise in the field.

How Often Should I Clean My Engine?

Cleaning your engine to improve cooling time is a great tactic, but you should avoid doing it too often. Engines are meant to have some presence of grease and grime so that the different metal pieces can interact without scratching or bumping. 

Most user manuals advise doing basic maintenance and oil changes after approximately 50 hours of use. For the average person, this amounts to roughly every two-to-three months, depending on the frequency of your use of the lawn mower. If your engine is new, you will need to complete an initial oil change within 7-10 hours of initial use.

Cleaning your engine does not mean a full breakdown and replacing of parts. This refers to simple maintenance of your mower, such as:

  • Changing the oil
  • Changing air filters
  • Adding new spark plugs

It is also important to protect your mower during the “off-season.” If you live in an area where it snows during the winter, you should winterize your lawn mower. This includes making sure that you:

  • Drain your mower of gas or add a fuel preservative
  • Wash off any visible debris
  • Sharpen the blades
  • Remove the battery and spark plug
  • Store your mower in a dry place for the winter

If you keep your mower in a place where rodents or insects can find their way inside, try and find a way to keep them out. Placing traps or using a repellent will ensure that mice do not find their way into your mower’s engine and chew through important wires or form nests that clog important air paths. 

Rodents can do a lot of harmful damage to your engine and wiring in your lawn mower. I have had good results with a couple of products by Grandpa Gus’s. I place the packets around my equipment and use the spray on the electrical wires to prevent rodents from chewing on the wires.

Conclusion

Cooling your lawn mower’s engine after strenuous use can be both simple and incredibly complex. You can take all precautions that you can find, but that does not guarantee that you will find the cause of your cooling delays or problems. 

The best thing that you can do is scheduled and regular maintenance. Maintaining a healthy lawn mower engine will give you the best cooling time possible while simultaneously providing the best output in performance. 

It should be noted, however, that you should not punch above your weight class. If you do not have the knack for working on mechanical systems, it is best not to poke and prod. You may end up doing far worse damage than any piece of debris you could have possibly hit.

Save yourself the hardship and time, find somebody with expertise that is comfortable getting some grease on their hands, and keep a cool head knowing your engine is in good hands.

My top items to keep on hand to service & troubleshoot your lawn mower

Socket & Allen Wrench SetOpens in a new tab. – Tool set needed to service & troubleshoot your mower problemsCarburetor CleanerOpens in a new tab. – Clean clogs & buildup in fuel system
MultimeterOpens in a new tab. – To check voltage, continuity & current to identify electrical problemsFuel StabilizerOpens in a new tab. – Stabilize & clean your fuel to minimize fuel system buildup
12-Volt Battery ChargerOpens in a new tab. – Battery/trickle charger to start your mower & slowly charge your batteryFilter WrenchOpens in a new tab. – Helps loosen your filter
Oil Drain PanOpens in a new tab. – To collect oil with spout to place in containers for disposalBattery Powered InflatorOpens in a new tab. – Keep your lawn mower tires inflated to prevent uneven cutting or steering issues

Powered Equipment Team

We're just a guy and a girl obsessed with outdoor power equipment! We are excited to share the knowledge and tips we have learned over our combined 55 years in the power equipment industry. We have both ran equipment dealerships and took pleasure in helping our customers everyday providing equipment repair, parts, purchasing, and business tips to our residential and commercial clients. We hope our blog will help you with your next purchase, repair, or project.

Recent Posts