Lawn Mower Stops Running When Gets Hot – How to Fix It

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Last updatedLast updated: March 04, 2021
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Now we’re back into a season when the lawns are no longer packed with snow and we can finally work on them. However, everywhere in the lawn is filled with thick grasses and there’s a lot of work to do. You finally started the mower and you’re on the job. Then, in the middle of it, the lawnmower overheats and dies. Now you’re wondering what are the possible problems when a lawnmower stops running when hot.

This is a common problem encountered by many users of lawnmowers. There could be several causes to this problem and therefore solutions.

The problem can be caused by several factors such as bad air intake, damaged carburetor, too dry carburetor bowl gasket, accumulation of gasoline in the tank, poor quality gasoline, and a lot more.

This article will help you discover the problem, give you the different troubleshooting actions, and how to prevent a lawnmower from overheating.

Vapor Lock

One of the causes of the situation when a lawnmower stalls when hot can be with the vapor lock. Unfortunately, one that is often overlooked, is when the hot gases inside the fuel tank cannot properly vent.

The gas flow in the system can reverse, due to pressure, hence, causing the gas to leave the carburetor and shutting the engine down. This is often called vapor lock.

That is, the engine cannot run the hot gases trapped in the tank. In lawn mowers, this problem occurs because of a dirty fuel tank cap. So, you have to replace or clean the tank cap.

Fuel supply and lubrication problems

Fuel supply and lubrication problems will cause the engine to stall, especially when it starts to warm up. Always ensure you check the engine’s fuel supply before making use of the mower and top up the oil as appropriate. You should change the engine oil once every 25 operating hours.  Empty gasoline that is in the tank for more than 30 days. This can spoil, turn sticky, and clog the fuel line. However, if you have made use of old or bad gasoline in the mower, you’ll need to thoroughly clean the tank and the fuel line,  replacing the fuel hoses and filters.

Carburetor doesn’t get enough gas

Lawn Mower Stops Running When Gets Hot - How to Fix It

You will want to check the mower’s fuel supply. There may have been an accumulation of gasoline in the tank because of partial obstructions which may affect the proper functioning of the device.

In this case, the gasoline does not reach the carburetor and thus causes your lawnmower to suffocate. You may have to clean the fuel line system or disassemble and clean the carburetor.

Furthermore, it is not recommended to leave petrol in the tank of your lawnmower to avoid breakdowns as much as possible. It is necessary to empty the tank after each lawn mowing. .

In any case, carburetor or fuel line problem is not an issue with corded lawnmowers. And one of the most recommended by our experts is the BLACK+DECKER 13 Amp 20-Inch (BEMW213) Lawn Mower, thanks to its height adjustability and ergonomic handle.

Problems with the compression

When your mower losses compression, there will be no enough pressure in the piston chamber which can squeeze fuel and air. Hence, there will be no spark and the crankshaft will not spin. Loss of compression can occur because of worn-out pistons or piston seals or because of a broken or bent pushrod.

Cooling problems

When the lawnmower’s engine cannot vent the hot internal combustion gases or take in fresh air in the next combustion stage, it can stall. Air enters through its air filter and exits via the muffler. Then, the air filter will become dirty quickly. It should be cleaned after every eight operation hours. The muffler must be cleaned after 60 operating hours. If they are too dirty to be cleaned, you may replace the air filter or the muffler.


  • In any case, if you find your lawnmower unredeemable due to long use and old age, then you may have to change it to get your lawn well-mown. According to most reviews, the sturdiest model must be the 21-inch & 170CC Lawn Mower from PowerSmart, which, thanks to its reinforced construction, is the most reliable option out there.

Lawn Mower Stops Running When Gets Hot - How to Fix It

Final thoughts

Since the mower burns gasoline inside the engine cylinder, an enormous amount of heat is generated. This heat must be dispersed outside of the engine to keep temperatures cool enough to maintain the correct pressures in all mobile systems in the mower. When a lawnmower shuts down after heating, it is usually caused by too much heat or pressure that has built up inside.

We’ve talked about the possible causes of the situation when a lawnmower stops running when hot. This can be caused by a bad air intake from the accumulation of debris. A damaged air filter can also cause failure. The same goes for a bad carburetor, a too dry float chamber gasket, a poor water supply resulting in partial clogging, or the fuel quality is not pure enough.

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