Skip to Content

Why Your Mower is Not Bagging Grass: Solved!

My friends use a mower with a bagger because they do not want grass tracked all over the place. Their children love to play outside and tend to track grass into their pool and through their house. A grass catcher is great to minimize the amount of grass clippings in your yard, but it can be a frustrating when it fails to bag your grass and leaves more grass clippings in your yard than it should.

A lawn mower may not be bagging grass because of a lack of air movement due to grass buildup under the mower deck, clogged blower tubes, worn blades or a slow engine speed. Bad belts, a worn fan or damaged blower housing in a belt-style grass collection system can cause your mower to not bag grass.

Prevent air flow restrictions by regularly inspecting your lawn mower and bagger system to keep it free of debris. I’ll go through all of the places to check clogging along with worn parts that may affect how well your mower bags grass.

Lawn mower is not bagging grass

This post may include affiliate links. Purchases made through these links may provide a commission for us, at no extra cost to you. As an Amazon Associate we earn from qualifying purchases.

Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing or operating. Consult a professional if you don’t have the skills, knowledge or are not in the condition to perform the repair safely.

Reasons Your Lawn Mower is Not Bagging Grass

Clogged Blower Tubes Prevent Bagging Grass

Remove the blower tubes from your bagger system, also known as a grass catcher. Inspect each tube for grass, sticks, dirt and other debris that may be clogging your tube. Scrape out any items collecting inside your blower tube.

Do yourself a favor and coat your blower tubes with a silicone spray that prevents debris from sticking to the insides of your tubes. Using this spray doesn’t mean you will never have to clean out your blower tubes again. It does mean you won’t have to clean them out as frequently. I suggest using the spray every other time you mow. Use a product like  Tite-Seal Mower Deck Spray.

Clogged Lawn Mower Deck Causes Bagging Problems

A lawn mower deck packed with debris can prevent the air movement required to push the grass clippings through the tubes. Your lawn mower won’t be able to efficiently bag grass if it can’t even get grass through the tubes. You need to remove any debris stuck to the bottom of your mower deck.

Gain access to the underside of your mower deck by securely lifting the deck in the air using jack stands or some other comparable item. With your mower turned off, key removed and spark plug wires disconnected, check your mower deck for debris.

If you notice grass buildup under the deck, use a deck scraper or wire brush to scrape the deck. Don’t lower the deck just yet. There are other items to check while the deck is in the air.

Clogged Grass Chute Prevents Mower from Bagging Grass

Next, look at the grass chute area. Clear the chute of old or wet grass that has built up in this area preventing grass from moving up into the tubes. You can also use a silicone spray inside the chute to help the grass flow better and prevent grass sticking to this area.

Worn or Damaged Lawn Mower Blades Can Cause Bagging Problems

Your bagging grass problem can be due to your blades not creating enough air movement under the deck to push air into the tubes. Take a look at your mower blades. Are they worn or damaged? If you notice the sails (this is the high sides of the blade) are thinning, you will not be able to move as much air so you’ll need to replace your blades with a new set.

Refer to my article on inspecting, sharpening and replacing mower blades for help with determining if your mower blades should be replaced or sharpened. I also include several methods to sharpen blades yourself.

Wrong or Incorrectly Installed Mower Blades Prevents Mower from Bagging Grass

Not all mower blades work the same. There are several different blades on the market today including mulching, gator, low-lift and high-lift blades. When using a grass catcher, you want as much lift and air movement you can get.

The best type of mower blade for this is a high-lift blade. The sail on the high-lift blade is higher so it can assist in creating good air movement under the deck. Check your blades to make sure you are not only using high-lift blades, but that they are installed correctly.

The sails of the blades must be pointed upward toward the mower deck. When the blades are installed correctly, a suction is formed under the mower deck that helps give you that nice cut and air flow. Read more about installing mower blades the correct way in our article, “This is the Way the Blade Goes On A Lawn Mower”.

Clogged Inlet Tube Causing Grass Bagging Problems

Your mower is using either bags or catchers to collect cut grass. Remove these from the hopper and look at the inlet tube for clogging. This is a common area for buildup. Clean any collection for grass from this area and replace the bags or catchers.

Plugged Inlet Screen Can Prevent Grass from Bagging

Because the inlet screen isn’t in plain sight, it is often overlooked when cleaning your bagger and removing debris restricting air flow. The inlet screen lets air leave the hopper so it can carry grass up the blower tubes. If this screen gets clogged, it no longer is able to create the air draft that carries the air clippings.

You will find the screen on the side of the grass hopper cover that isn’t exposed to you. This is why you may miss checking it. Brush the screen off with your hand. If the buildup is bad, you can use a wire brush. A silicone spray can be used on the screen. Make sure the spray dries before you begin bagging grass.

Bad Deck Belt or Blower Belt Can Cause Mower Bagging Problems

A deck belt or blower belt can cause your mower not to properly push grass clippings up the blower chute if you are using a belt-driven grass collection system. A belt-driven system uses an added fan to blow grass clippings.

The mower deck belt drives the blower belt for the fan. If either of these belts are worn, they can fail to operate the fan required to push the grass clippings up the tube. Replace your belts if they appear to be worn with a glazed shiny appearance, cracking or fraying.

Worn Fan or Bad Bearing in the Blower Housing Prevents Bagging Grass

If you have a belt-driven grass collection system that uses a fan, the fan blades or blower housing may become damaged or worn causing a loss of air flow needed to carry the grass clippings into the hopper. The fan, sometimes called an impeller, must be replaced if the blades become worn. You need to check for gaps between the fan and the blower housing. You will lose air flow if the gaps to too far apart.

Bearings located on the fan shaft can eventually wear or become damaged. String or long grass can wrap around the fan shaft and cause your bearings to go bad. To replace the bad bearings, you’ll have to disassemble the housing on most blower housings.

Slow Engine Speed Can Cause Your Mower Not to Bag Grass

Engine speed is crucial to the success of bagging your grass. You need to keep your engine running at its maximum horsepower when running your grass catcher. So run your lawn mower at full throttle. Most engines need to run about 3200 to 3650 rpms to give you the most power out of your engine.

If you notice your engine doesn’t sound like it is running and giving you the power it usually does, you may have a problem with your engine. Bring your mower to a small engine mechanic to diagnose whether the problem is in your engine.

Ground Speed Can Affect How Much Grass is Bagged

Running your lawn mower too fast will not only put extra load on your engine, but it can also fail to allow your grass catcher the chance to pick up the grass. Slowing down your ground speed will allow your mower to better be able to handle the flow of cut grass.

Mower Won’t Bag Wet Grass

Cutting wet grass and attempting to bag it will not be a good experience. Wet grass will cause all kinds of issues. It is heavier and stickier than dry grass so it tends to collect in all the places you don’t want it. Grass will collect under the mower deck along with in the chute, blower tubes and inlet tube.

This increased buildup will restrict air flow through the grass collection system. Wait to cut grass until there is no dew on the grass or it is no longer wet after a rainfall. Believe me, waiting for your lawn to dry out before you cut it will save you the pain of cleaning your bagger system and scraping your deck. It will also allow you to bag more grass and not lose it due to air flow restrictions.

Wrong Bags or Damaged Bags Will Cause Problems Bagging Grass

You can’t use just any old bags on your grass collection system and hope they work. Some of the older grass catchers use bags that are made of cloth. These can sometimes be repaired if they get a hole in them.

Today’s grass bags are made from a mesh type material that is loosely knitted and made from a nylon or polyester material. These types of bags are designed to allow air movement through the mesh. Without air being allowed to escape the bags, the bags would just continue to expand and eventually burst at the seams. Make sure you are using the correct bags that are designed to fit your bagging system.

Grass Bagging System Not Correctly Installed Can Cause Bagging Problems

Check your grass bagging system for correct assembly. You need to make sure every component of your bagger is securely in place and there isn’t any area where air can escape. The biggest problems you can experience when trying to bag grass is the loss of air flow. Seal up any areas that can reduce air flow so grass can’t be properly carried up the tube into your bags.

Summary

To avoid having a mower that doesn’t bag grass, follow these simple tips:

  • Don’t mow wet grass
  • Run your engine at full throttle and slow down your ground speed
  • Use a silicone spray to coat the underside of your deck, blower tubes and inlet screen to reduce the amount of grass buildup
  • Scrape your deck regularly and run good sharp mower blades
  • Check for any areas of the bagger system that are not tightly sealed and can allow air to escape