Seized lawn mower engine is an issue that can be a frustrating experience for homeowners. By understanding the causes and taking preventive measures, we can save time and money in the long run also, knowing the causes is the most important thing when it comes to a seized lawnmower engine.

Seized Lawn Mower Engine

Let’s look at the factors that cause the lawn mower to seize.

Factors That Are Causing Your Lawn Mower Engine To Seize

The factors that are causing your lawn mower engine to seize are the lack of lubrication, overheating issues, or having a dirty air filter. It could also be due to the lack of use, fuel-related issues, or mechanical failures taking place.

– Lack of Lubrication

A lack of lubrication in the engine is one of the most common reasons of a seized mower engine. Lubrication is significant in ensuring that the components of the engine run smoothly by reducing friction. As a result, the machine would slow down and seize from functioning well.

The components that require lubrication include the pistons, bearing, connecting rods, and crankshaft. These must be well-lubricated in order to work together without friction. It is most likely that when a lawn mower engine seized no oil has been applied, and this would be a common cause. There are various motor oils you can use, such as SAE 30 and SAE 40.

– Overheating

Another common reason for seized mower engines is overheating. The lawnmower engine’s combustion process generates heat while the cooling system regulates the overall temperature.

When it overheats, the engine can expand and cause excessive friction. Eventually, the engine will hold off from its functionality, and this is because the motor is quite hot at the moment, more than usual.

Overheating is often caused by damaged or dirty cooling fins, clogged air filters, or the cooling system’s circulation issues. Sometimes, the engine’s timing may be off. This can cause it to work harder than required, leading to overheating.

– Dirty Air Filter

Air filters are responsible for preventing dirt and debris from entering the mower engine. Dirty ones can cause the engine to run efficiently and quickly overheat.

Clogged air filters restrict airflow, causing the engine to work harder, and the air filters would fill up with dirt. The added stress causes the engine to overheat and seizes the engine, and the motor gets tired from functioning and the heat.

– Lack of Use

When a lawnmower sits for an extended time period without use, the engine can seize. The usual culprits are rust and corrosion, which are caused when moisture builds up in the engine. As a result, the components inside are compromised and start slowing down the machine’s life span.

Factors of Causing Lawn Mower Engine To Seize

In some cases, the fuel left in the engine can eventually turn into varnish and this is due to staying in for so long. This causes a buildup of debris that can clog the components of the engine. The debris buildup causes the components to function poorly, leading to engine seizure and even failure.

– Fuel-related Issues

Low-quality fuel or debris in the fuel system can cause the lawn mower to seize. Old or contaminated fuels can result in difficulty starting the engine, reduced power output, carbon buildup, and fuel system damage.

Lawn mower engine seizure is the result of the engine running poorly and causing different issues in the long run.

For instance, it could be due to ethanol, which is a component in gasoline, attracting a quantity of moisture. In this case, note that the amount of humidity that would buildup can cause rust and corrosion in the engine’s components. In some instances, debris in the fuel system causes damage to the components of the engine, causing it to seize.

– Mechanical Failure

Broken connecting rods or damaged pistons are examples of mechanical failures that are often experienced by seizing riding lawn mowers. Usually, mechanical issues are the result of a lack of regular or preventive maintenance. At times, mechanical issues arise due to the prolonged use of the machine, as well.

The Solutions That Prevent a Seized Mower Engine

The solutions that prevent a seized mower engine would be to provide regular maintenance and avoid prolonged use. You should also try to use high-quality fuel, and store the mower correctly in the winter. Address the mechanical issues immediately and break in the engine correctly.

– Regular Maintenance

Regular maintenance is essential in preventing seized lawnmower engines. The recommended engine oil change intervals must be followed as suggested by the manufacturer in the owner’s manual. This includes checking the oil level before every use, ensuring that the airflow filter is free of dirt and debris, and being keen on these details.

Additionally, checking the spark plug should be part of regular maintenance, because at times it may be the result, and fixing it would solve the issue.

Aside from the spark plug, the carburetor should be cleaned, and the engine inspected for wear and tear. Once the engine becomes well-maintained, it will be less likely to experience overheating or mechanical failure.

– Avoid Prolonged Use

Overheating is caused by dirty engine components as well as prolonged use, especially in hot weather. Keep the engine’s cooling system in good working order. You can do this by cleaning the radiator and inspecting its hoses for leaks or damage.

The engine’s cooling fins should be regularly cleaned to keep debris away and allow for proper airflow. If overheating is still occurring, the mower should be turned off and allowed to cool down before using it again, and wait for it to normalize the temperature and then use it.

– Use High-quality Fuel

Avoid ethanol-blended gasoline to reduce moisture buildup. Instead, use high-quality fuel to prevent fuel-related issues that cause your riding lawn mower to seize. Go through the owner’s manual from the manufacturer to view the recommended fuel.

Solutions That Prevent a Seized Mower Engine

Additionally, it is important to use fresh fuel and to abstain from old or cheap ones. Old or contaminated fuel can cause engine issues, especially with the spark plug, and should be completely avoided. Using high-quality fuels reduce engine and component issues, resulting in better lawnmower performance.

– Store Lawnmowers Correctly

Lawnmowers should be properly and safely stored to prevent engine seizures. Before storing your lawnmower for a long period, the fuel tank should be drained to prevent varnish buildup.

Additionally, the oil level should be inspected and topped off. Keep the mower in a dry and protected area. This will prevent rust and corrosion from occurring as a result of moisture buildup, and for the machine to be functioning in a lacking manner.

– Address Mechanical Issues Immediately

Whenever mechanical issues occur, they should be addressed as soon as possible. Unusual noises, vibrations, and performance issues are signs that your lawnmower requires attention for repair or maintenance.

By addressing them immediately, you can prevent more severe problems from developing. Once the issues have been addressed, maintain regular inspections and maintenance to identify potential mechanical issues before they result in significant damage.

– Break In New Engines Correctly

It is important to follow the instructions from the manufacturer when using a new mower for the first time. Even though it has a small engine, the lawnmower still requires proper breaking-in protocols.

Failure to comply with the manufacturer’s breaking-in protocols may lead to improper wear or overheating. Unlike a push mower, gas-fueled ones require the engine to be properly conditioned to reduce the risk of engine seizure in the future.

Regular Maintening Lawn Mower Engine


When you have your engine seized, it is a frustrating experience especially when you need to mow the lawn right there and immediately. With all the causes and solutions identified in this article, let’s go over some significant points:

  • Lack of lubrication and dirty air filters can cause your lawnmower engine to overheat and seize up.
  • Lack of use, fuel-related issues, and mechanical failures are the next common reasons that cause lawnmower engine issues.
  • Prevent lawnmower seizure issues by keeping the engine well-maintained, using the mower regularly, and filling it with high-quality fuel.
  • When using mowers for the first time, break them in correctly and store them in dry, protected areas to avoid moisture buildup.
  • When mechanical issues arise, address them promptly to prevent more serious issues in the future.

The next time you have mower start up issues, you will know what to do. While engine seizures are concerning, use our article as your checklist to determine the causes and prevent them from happening.

5/5 - (19 votes)
Evergreen Seeds