Overheating John Deere Mower Motor (8 Reasons & Fixes)

You notice a slight heat odor coming from the engine. In order to prevent further damage to the mower’s engine, you should pull the plug and investigate the cause of the problem before continuing to use the device.

Overheating can occur in a John Deere lawn mower’s engine if the oil level is too low, the wrong type of oil is used, the air filter is clogged, the cooling fins are blocked, or the engine guard is missing.

It is possible to overheat the John Deere’s engine if the mower deck is clogged, the blades are dull, or the ground speed is too high for the length, thickness, or wetness of the grass.

Always remember to exercise caution when operating a John Deere and stick to the guidelines laid out in the manual. Before making any repairs, you should turn off the mower, take out the key, let the engine cool completely, and then remove the spark plug boots.

Before diagnosing, repairing, or operating, be sure you’ve read and understood all of the safety recommendations in the equipment’s operator’s manual.

If you are unsure about how to proceed or if you lack the necessary expertise or experience, you should seek the assistance of a professional.

John Deere Lawn Mowers Overheat—Why?

Problems with a Gas-Powered John Deere Mower Due to Incorrect Engine Oil

With a gas-powered John Deere mower, the engine oil has two purposes: it lubricates the engine so the moving parts can do their job, and it helps keep the engine cool.

Oil for an air-cooled tiny engine is different than oil for a liquid-cooled one.

John Deere lawnmowers, tractors, and zero-turn mowers employ gas-powered, compact engines (such as Kohler, Briggs & Stratton, and Kawasaki) that require air-cooled, zinc-rich engine oil. An addition used as a refrigerant, zinc is a versatile metal.

Due to its usage of liquid water for engine cooling, regular motor oil like that found in cars does not contain a lot of zinc.

See the table below for recommendations on which oil to use at various temperatures. Have a look at this table and the handbook to see what kind of oil you should be using.

Most small engine manufacturers, like those who make the engines found in John Deere mowers, advocate using SAE30 or 10W-30 engine oil.

But, you might need to switch to a 20W-50 oil viscosity while working in warmer temperatures and a 5W-30 oil viscosity when working in cooler temperatures.

The ANSWER is to change the oil and replace it with the proper oil for an engine that operates in an air environment.

John Deere Lawn Mowers Overheat—Why?

John Deere Mower With Low Engine Oil Level

To ensure smooth motion of the engine’s internal components, regular lubrication is essential. Low oil levels cause the engine to overheat due to increased friction.

If you keep an engine running with a low oil level, the oil will thicken. This is a certain way to wreck an engine.

Before you start the mower, make sure the oil is at the proper level. If you discover it to be low, add a small amount of oil.

You should check for the following if your John Deere mower is often needing more oil:

  • Leaking Oil – Inspect the engine compartment for oil leaks. As soon as the source of the leak is located, the leaking gaskets should be replaced.
    If your lawnmower has a filter, check that out too. Verify the tightness of the oil filter’s seal.
  • Inspect for a clogged air filter if you notice your oil burning. If your air filter is clogged, your engine will have to work harder to prevent the oil from burning. If the filter becomes too dirty to clean, you should replace it.
  • Overheating during operation can cause an engine to consume oil. An issue with the valves or rings could potentially be the cause. Get the engine checked out at a service station for your mower.

THE SOLUTION: If the engine oil level is low, fill it up. If you suspect dirty oil is to blame for your engine’s unpleasant odor, a comprehensive oil change should be performed. Perhaps the oil thickened as it was heated.

Even after an oil change, your John Deere may have been severely damaged from operating with insufficient oil.

If your lawn mower needs servicing, you can take it to a John Deere dealer or a store that specializes in small engines. To fully assess the situation, the technician will need to do more tests.

John Deere Mowers Have Damaged or Blocked Engine Cooling Fins

Engine cooling fins direct airflow out from the interior of the cylinder head and engine block, where it can evaporate into the atmosphere.

  • A fan is located on the top of the motor. It draws in cool air from outside and directs it downwards into the engine.
  • Hot air is evacuated from the bottom of the engine after being routed through all of its heated components.

Damage to the cooling fins or a buildup of dirt on them can prevent them from circulating enough air around the engine. An overheated engine is a potential result of this.

The answer is to take off the top of the engine and clean the radiator. You need to replace any broken fins you find. Clean up the area surrounding the engine and the cover.

Hereafter, include this in your regular annual upkeep.

It’s not a good idea to wash the engine of your John Deere, since that will only push dirt and water farther into the engine. If you’re having trouble starting your mower, don’t make the problem worse by spraying water into the engine while cleaning it.

John Deere Mower Without Engine Guard

It is imperative that the engine shield be installed so that cool air can flow around the engine and keep it from overheating. When the watchman isn’t there, the area loses its calm atmosphere.

The problem can be fixed by making sure the engine guard is in the right spot. Secure the guard by tightening or replacing its mounting screws. Substitute a new guard for an old one.

The John Deere Mower’s Filter Clogged Up

Using an air filter helps guarantee that the motor always has clean air to breathe, preventing premature engine failure due to dirt.

Unless the filter is regularly maintained and cleaned, it can get so clogged with dirt and debris that it prevents air from reaching the engine.

The John Deere engine may overheat if it needs to work harder to dissipate the excess heat.

ANSWER: Take out the filter and look at it. Put the paper piece under a flashlight beam. If the amount of light is satisfactory and the filter appears to be in good condition, you can clean it by tapping it against a hard surface before replacing it.

However, a new filter should be installed if the illumination is poor or absent, the air filter is damaged, or if it appears particularly dirty and dark in color.

The inner air filter and pre-filter are two components of the air filtration system used by some John Deere mower engines. A foam pre-cleaner may be used by some, which is wrapped around a traditional paper air filter.

These filters provide extra defense for the motor by collecting debris and keeping it out of the intake system.

If you want your mower to last as long as possible, you should clean and replace the air filter at regular intervals throughout the year.

If you use your John Deere mower in dusty conditions or more frequently than the typical homeowner, you may need to repair or clean it more frequently.

Don’t skimp on maintenance by using a high-quality air filter that will last as long as feasible. Even though I try to save money whenever possible, I can’t help but invest in upkeep necessities.

The cost of replacing the air filter is much less than the cost of repairing or replacing the engine because of junk entering the engine cavity.

Cluttered John Deere Mower Deck

Under the mower deck, grass trimmings, dirt, and other debris will accumulate. This necessitates routine scraping of the John Deere deck.

For a clean shave, the space under the deck is employed to generate wind. Mower blades, baffles, and deck are all engineered to maximize suction and airflow for a clean, uniform cut.

The engine has to work harder to move the blades through a packed mower deck, lowering cut quality and increasing fuel consumption.

Use a deck scraper to remove debris from the mower’s deck. Alternatively, you might use a putty knife or wire brush.

Inspect the mower deck often to ensure it is clean.

You can purchase materials to apply a coating to the underside of the mower deck, which will aid in preventing buildup. Although these items may help, you can still expect some accumulation despite their use.

Don’t mow wet grass, and keep the throttle fully engaged to prevent clumping and buildup beneath the deck.

Worn-Out John Deere Mower Blades

The issue of a clogged mower deck will be exacerbated by dull mower blades.

The engine will have to work harder, and it may overheat as a result, if the blades have to be turned through trash under the deck while they are dull.

The ANSWER: Maintaining sharp mower blades is a must. A typical homeowner should sharpen their mower blades twice a season, or every 25 hours.

If you want to learn more about how to balance and sharpen your John Deere mower’s blades, check out Replace & Sharpen Your John Deere Mower Blades.

Damage to a John Deere Engine from Over Use

It’s important to take stock of your mowing circumstances if you want to maximize the efficiency of your John Deere mower.

Whether the grass is tall, thick, or wet, it might place a strain on the engine while you’re mowing the lawn. The device could overheat if you do this.

The solution is to reduce the ground speed of the mower when cutting long, thick, or damp grass. If you want to get a good trim without taxing the engine too much, try these strategies.

  • When possible, postpone grass mowing until the grass is dry.
  • Twice or even triple cut the tall grass. Mower deck height is increased to its maximum position. Attempt the first incision.
  • The next step is to make a second cut, but this time at a shallower height.
  • Put the mower’s engine through its paces at top speed.
  • When mowing lengthy, thick, or damp grass, slow the mower’s forward momentum.

Cool Down Your John Deere Tractor After Cutting The Grass

It’s crucial to let the engine cool after using a John Deere lawn mower before putting it away.

A John Deere mower should ideally be kept in the open air. If the engine on your John Deere riding mower is concealed beneath the hood, you can see it by raising the hood.

The lawnmower should be allowed to run with no obstructions. Your engine will start cooling down through regular means.

Read our article Lawn Mower Engine Cooling Times Explained to find out how long an engine needs to cool down and what other elements influence this process.

Is Your John Deere Mower Still Giving You Trouble?

Owners of John Deere mowers are subject to a wide range of issues over the product’s lifetime. Some of these issues include starting, shutting off mid-mowing, vibrating excessively, cutting unevenly, or just not moving.

I compiled a useful guide for diagnosing issues with your John Deere mower so you can figure out what’s wrong with it. See the article “Common John Deere Lawn Mower Issues and Solutions” for help.