Why Does My Mower Not Cut All the Grass? (Solved!)

When your mower doesn’t cut all the grass, it could be because there is an issue with the mower. You should check the deck, blades and engine to make sure they are in good working order and adjust them as needed. Changes in when and how you mow could also assist you in getting a perfectly mowed lawn.

In this article, we are going to share information on how to check your mower for damage, do basic maintenance, and share some tips on other ways that could make mowing the grass easier and ensure all the grass is cut. Please refer to the owner’s guide for your mower before doing any maintenance work.

Check the Deck

The mower deck is one of the most important parts of the mower. If this is not in good working order or uneven, you could experience your mower not cutting all the grass. Here are some things you can do to ensure it is in good working order:

  • Turn off the mower and unplug the spark plug to prevent the mower from starting, then, while the mower is lying flat, measure the height of the blades.
  • If these measurements are different, put on heavy gloves, turn the blades then measure again. If they continue to be different, you may have a bent blade.
  • The tabs controlling the height of the deck can be found at each of the wheels. Make sure all the tabs are in the same slot on each wheel.
  • Make sure there is no rust or damage to the baffle or any part of the deck.

Another issue to check is a build-up of grass and dirt underneath the deck. Tip the deck on its side and use a putty knife or stick to dislodge the grass or caked up dirt.

Blade Issues

A common cause for your mower not cutting all the grass is an issue with the blades. They could be bent, dull, or have other damage. Blades should be checked at the start of the grass cutting season to ensure they are sharp and not damaged in any way.

  • If the blades are dull, they should be sharpened.
  • If there is damage to the blade, such as a missing blade tip, it should be replaced.
  • Always make sure the bolts holding the blades in place are tightened to prevent wobbling.

Mower performance is also impacted when the blades are not in good condition. A sharp, undamaged blade allows for faster cutting and results in less power needed, which can also extend the life of the engine.

Damaged or dull blades can also cause the grass to be damaged. This can result in longer healing times for the grass and the potential for the grass to have jagged edges and the tips may turn yellow.

Watch this video on how a blade cuts grass to understand the importance of a sharp blade.

Maintaining the Engine

A properly maintained engine will make it possible to run at full throttle, which will allow the blades to rotate at optimum speed. Make sure the throttle is set properly and is set to fast when cutting.

Make sure to give the engine a tune-up. Then, through the season, you should change the oil at least every 50 hours of usage and clean the air filter about every 25 hours of use. The air filter should be cleaned more if there are dry, dusty conditions.

Fuel that is more than a month old will contribute to poor engine performance. The fuel can become stale and may gum up the carburetor, which blocks the fuel feed ports and can cause fuel starvation.

When to Mow

Choosing when to mow your lawn can have a major impact on the grass being cut properly. If you have flexibility and can choose when to mow, the best time of the day is mid-morning. This is when any overnight moisture will have had time to dry and before the heat of the day has had time to settle in.

The second-best time to mow is in the late afternoon when the heat will be subsiding. This will also give the grass time to heal before nightfall.

The worst times to mow your lawn are in the early morning, which is when the grass could still be wet, and evening, which doesn’t allow time for the grass to heal.

Tips on Mowing

There are some simple things you can do to help make sure the mower cuts all the grass properly.

  • Do not mow wet grass. This can cause build-up of grass underneath the deck.
  • Check to make sure there is no grass or dirt build-up before mowing.
  • Overlap each row by a few inches, which will ensure that all the grass is being cut.
  • Before you start to mow, make sure all debris, such as sticks and rocks, are removed as they can cause damage to the mower.
  • Check for nesting small animals.
  • Only cut one-third of the grass blade to ensure a healthy lawn.
  • Wait until the grass is three-inches tall before cutting it, this is especially important for new grass.
  • If the grass is overgrown, still follow the guidance to cut one-third of the grass blade and lower the height over time until you reach the height you desire.

Lawn Health

The health of your grass will impact your ability to cut all the grass. Damaged grass can lead to an unattractive lawn and introduce disease.

  • Make sure your blade is sharp for smooth cuts.
  • Water the lawn when it needs moisture. Watering is best done in the early morning to allow the water to reach the roots before the heat of the day settles in.
  • Damaged grass can develop fungal infections and other diseases.

Final Thoughts

A well-maintained mower and following our tips on when and how to mow will guarantee you have a beautiful lawn every year – follow these tips for a well maintained lawn that will turn your neighbours green (pun intended).