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Lawn Mower Spitting Out Grass Causes and Solutions

A lawn mower is a machine that cuts grass by rotating a fixed blade called a rotary cutting head. The operator controls the speed of the cutting head using a rope or drive cable that connects to the rotating blade, causing it to move in one direction or another. 

Sometimes these machines catch problems like it’s spitting out grasses. Whenever you try to mow with it, it spits grasses front and side. 

In this article, we’ll discuss this problem and some of the potential solutions to this problem.

Lawn mower isn't collecting grass, a man is checking in his lawn
Lawn mower not collecting grass

Reasons why lawn mower spitting out grasses

One of the most common problems that lawn mower owners have is that the mower spits out too tall grass. They may not realize it, but the blades of their lawn mowers are usually a bit short for tall grasses. 

That is why grasses end up being too thick and dense, making it difficult for the blade to cut through them. Another reason would be if the deck gets clogged by grass, which causes it to slow down and stop. 

Some lawn mowers might have clogged chutes and defective tires which can cause uneven cuts and bumps in terrain. Mowing at a fast speed might cause uneven cuts as well.

Most of these reasons can be fixed by carefully checking what type of blade, deck and tires you have on your lawn mower and adjusting your speed accordingly.

Too tall grasses

Lawn mowers are all made to do their job. When the grass is too high, they spit out the clumps. This makes it harder for the user to see where they are going and leads to a bad situation.

Tall grass can be a problem on your lawn. It can become difficult to mow and it can get clogged up under the deck. This can cause a Lawn Mower to spit out grass at strange angles and clog up variety of things under the deck. 

You may also notice grass is spitting out the sides and front. You need to be careful when you are mowing your lawn because too tall grass is dangerous for any machine that runs over it. 

In case of low cutting height, the grass can clump together and cause the mower to spit out grass or not cut the lawn at all. Try to raise the deck height and do this again.

The grass is Wet

Lawn mowers are a necessary tool in any lawn care and maintenance. When the grass on the lawn is wet, it can be more difficult for a Lawn Mower to cut through when compared to dry grass. 

However, there are times when the blades will get clogged with wet grass and this is a common problem that plagues many users of these machines. The Lawn Mower will spit out clumps of grass when it encounters wet grass, interfering with the ability of the blades to cut. 

They won’t throw far, and you must collect them in a mow bag after every few minutes. You will need to go back and either collect or break up and distribute. 

The blades of your lawn mower are very sharp, but when they encounter wet grass, they can get weak overtime. Wet grass can cause rusting and discoloration on parts of it.

Make sure to clean the chute every now and then or collect the spit out clumps after mowing.

Wrong Type Blade

Lift mower blades create suction that pulls the grass and cuts it nicely, but they might also cause a lawn mower to spit out grass. This depends on whether or not the motor is installed in the machine. 

Lift mower blades come in a variety of forms and sizes. Other lifts have varying amounts of lift depending on what type of job is being done. The mower’s motor has to rotate fast to achieve the level of lift to work properly. 

If it’s not done properly, you’ll notice grasses chopped unevenly and flying clipping around.

A Clogged Chute

When the discharge chute becomes clogged, it can cause a lawn mower to spit out grass in different directions. It can become clogged with debris or small plants that are growing in between the blades of grass. 

Clogged Chute in a lawn mower
Clogged Chute

The discharge chute has not been cleaned in a long time and as a result, the grass has become really compacted, making it more difficult for the mower to pull it out of the way. 

It is important to keep the discharge chute of your lawnmower clean so that it doesn’t get clogged and spit out grass in different directions. In order to prevent this, you should ensure a clean chute before you use it.

Clogged Deck

A smooth deck underside that is free from clumps or debris ensures the best possible lawn cutting experience. The lawn mower’s underside should be clean and free of any obstruction, allowing the grass to pass smoothly through the machine.

Clogged deck in a lawn mower
Clogged deck in a lawn mower

When the underside of a Deck is clogged with grass, it causes a Lawn Mower to spit out grass. 

This occurs when the blades of the lawn mower have an unimpeded path to the chute, which is what allows them to get stuck in a clotted area. There are two ways to prevent clogs when using a Lawn Mower. 

One is to get a Teflon coated or sprayed deck; this will prevent grass from accumulating and the other way is to move the machine to a suitable space as cleaning gets a little messy.

Underinflated Tires

Underinflated tires can be caused by a tiny puncture. When the tire has a small puncture, it causes air to slowly leak out which can cause the lawn mower to become unbalanced. 

When this happens, one side of the lawn mower will be higher than the other which can lead to a minor cut. A little unbalance in psi will cause the lawn mower to ride unevenly. It will eventually cause the mower to spit out grass.

A Poorly Fitting Grass Catcher

The grass catcher is an important part of your lawn that catches the grass clippings from your mower, so they don’t fall on the ground and turn into a mess. If it’s not installed properly, then it won’t be able to catch anything, and you will end up with a big mess. 

When you mow, the clippings are collected in a grass catcher that is usually attached to the underside of the mower. A poorly fitting grass catcher can cause many problems for your lawn mower. 

If your grass catcher doesn’t fit properly, it can cause clippings to get into areas that they shouldn’t be – like underneath your mower. It is very easy to fix a poorly fitted grass catcher. 

But if the catcher is broken, you’ll need to replace the component to work it again.

A Thatched Grass Catcher

The main function of grass catcher is to capture the clippings into a bag before they blow away, so they don’t get stuck in the air filter, obstructing airflow, and causing damage to the engine operation.

A thatched grass bag can interfere with airflow and cause a Lawn Mower to spit out grass clippings. This can prevent the grass clippings from being carried out and hinder mower’s performance in terms of cutting quality and quantity.

Mowing speed is too fast

The bagger system on a lawn mower is very important in keeping the grass in the bag. But when you have too much speed, it may not be able to keep up and clippings will be missed. 

It may also cause the mower to spit out grass right below the deck which can become a safety hazard. The bagger system is one of these areas that need to be maintained properly for continued use.

Engine’s Performance

When the engine surges or it is not running properly, the mower will spit out grass because it cannot cut it as smoothly as it should.  If the engine is not set to the correct mixture, then it will not be able to get the appropriate speed for cutting. 

Lawn mower engine
Lawn mower engine

When adjusting the throttle, one should make sure that it is set correctly and so that it can run at a rapid pace when cutting. If the motor is in good operating order, then it should be fine.


If your lawn mower is spitting out grasses, try to find the reason and our guide will help you in this process. Try to fix by yourself, and if you can’t fix by yourself, get help from professionals.

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