Exmark Lawn Mower is Vibrating: Solved!

Riding on my Exmark zero turn is not always the smoothest ride when I’m mowing an area of the yard that has mole tunnels running through the ground.

This last time when I was mowing, I felt a vibration that was more than just running over some bumpy ground. I went through the steps to isolate the vibration. 

Exmark lawn mowers may begin shaking and vibrating due to the loose engine mounting bolts, the electric clutch, unbalance blades, freight matter wrapped around the blade shaft, bad bearings in the spindle housing, bad pulleys, or debris wedged in the lawn mower. 

I am going to take you through the steps to check your lawn mower over when you experience your Exmark shaking. 

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

Troubleshoot Your Exmark Lawn Mower Vibration 

Take Safety Precaution to Prevent Mower from Starting 

Do not skip this step to ensure your engine will not start while working on your Exmark mower deck. 

·      Turn off the ignition 

·      Remove the key 

·      Remove the spark plug boot(s) for safety 

Check Engine Mounting Bolts

Engine mounting bolts are designed to reduce the vibration of the mower when the engine is running. Make sure the engine mounting bolts, also known as motor mounts, are tight. If any bolts are missing, broken, or worn, you must replace them. 

On a push-style mower, you will want to check the engine mounting bolts when you feel a vibration once the mower blades are engaged. 

Check the Clutch 

There are different types of clutches. An electric clutch will have a ball bearing that can fail to cause vibration. A manual engagement clutch, with belts and pulleys, will have bushing and linkages that can fail. 

Push mowers do not use a clutch. You will have a blade engagement lever that should be checked. 

Inspect Your Mower Blades 

Blades installed on an Exmark mower must be balanced. An unbalanced blade can cause your mower to start shaking. A blade can become unbalanced when it is worn more on one side over the other. 

An unbalanced blade can be a result of sand wearing the blade unevenly or sharpening the Exmark blade incorrectly. Read more about mower blades and sharpening them here. 

If you have recently replaced your blades, make sure you installed the correct sized blades with the right blade length and center hole size.

Also, make sure you installed them correctly using the correct hardware. Some mower blades use washers and bolts while others also use splined bushings. 

A good way to ensure your mower blades are balanced before you install them on your lawn mower is with a blade balancer. 

You can also use a nail on the wall to make sure the blade is balanced. If you use a nail, place the center hole onto the nail. The blade should stay level. If it is weighted more to one side, you will need to continue sharpening on that side until the blade hangs level. 

Check for Foreign Material Around Blade Shaft 

You take the necessary steps to make sure your yard is free of toys, debris, and other materials before you begin mowing, but it doesn’t always mean you missed something.  You could pick up items that wrap around your mower blade shaft that can cause your mower vibration. 

It’s important to inspect your mower deck for damages as I write out here. Look at the top of the blade and check to see if there is any foreign material wrapped around the blade shaft such as wire or string. 

If you find any items, remove them and check to make sure this didn’t cause any further damage to the blade shaft, also referred to as the spindle. 

Check for Bad Bearings in the Spindle Housing 

Inspect the bearings in the spindle housing on your Exmark lawn mower. To do this, you will need to grab a hold of both ends of the mower blade and rock it up and down. Make sure you wear a good pair of heavy work gloves as the blades can be sharp. 

There should not be movement in the blade.  If there is movement, the bearing is bad and needs to be replaced. Exmark uses sealed bearings in its cutter housing assembly. They do not offer the option to only replace the bearing. You must replace the cutter housing assembly. 

Some Exmark owners choose to find a bearing that matches in size and repair the cutter housing. From my experience, it does not last as long as replacing the whole cutter housing assembly. 

Worn Exmark Belts and Pulleys 

Remove the belt covers and lift up the floor pan to gain access to your belt and pulleys. It is necessary to keep this area clean and free of debris when you are performing your regular lawn mower cleaning.

This will help keep your deck running smoothly and prevent a fire due to the heat of the belt and dry debris. 

Inspect the condition of the belts and pulleys. Look for wear on the belt and bearings in the pulleys. You can identify a bad bearing in a pulley by checking to see if you feel any resistance or hear bearing noise when you hand-turn each pulley.

You will also want to check the bearing and bushing on the engagement linkage. 

Debris Lodged in Your Mower 

When mowing, the lawn mower kicks up all kinds of small debris. Some of these items can get lodged into various parts of the mower. You will be surprised to know a small acorn, wood chip, or other small debris can cause your whole mower to shake. 

A small piece of wood caught under a pulley on your mower deck can cause a vibration. Every time the belt runs around the pulley, the belt can cause a vibration that rattles the complete mower deck. 

You need to look over every part of your mower to make sure a little piece of debris is not lodged where it should not be. 

Don’t Skip Regular Mower Maintenance 

Not only should you clean your Exmark lawn mower regularly, but you also need to complete regular Exmark maintenance during the year and prepare your mower for storage at the end of the year. 

Doing so will extend the life of your Exmark mower and its engine. I have a few guides to assist you with maintaining your Exmark.  

For a guide on performing a hydraulic service your Exmark read “How to Change Exmark Zero Turn Hydraulic Oil & Filter”. 

For preparing your Exmark for storage at the end of the mowing season read “How to Winterize Your Exmark Lawn Mower”.