We often overlook our lawn mower’s cutting deck when it comes time for maintenance and servicing. Even though the cutting deck is probably the part that gets the most wear and tear, it is sometimes neglected. So, what does it take to inspect a cutting deck, and what should you look for? Well, let’s go over how to inspect a riding lawn mower cutting deck, including all the different components.
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What to Inspect on a Riding Mower Cutting Deck
The cutting deck is one of the major parts of any lawn mower and is made up of several mechanical components. To ensure you get the best cut from your lawn mower, you want to ensure that you routinely inspect each of the components. Here is a list of all the parts of a riding lawn mower cutting deck you need to check.
- Pressed/Fabricated Cutting Deck Structure
- Deck Mounting System
- Pulley System
- Idler Pulley System & Tensioner
- Grease Fittings
- Protective Guards
Different Parts of a Lawn Mower Cutting Deck
It may look overwhelming but don’t worry. I’m going to break down what all the parts are and tell you exactly what you need to look for. Let’s dive in and go over riding lawn mower deck maintenance.
Pressed & Fabricated Lawn Mower Cutting Decks
There are two main types of decks: pressed and fabricated. A pressed deck is made from a single piece of metal that is pressed into a mold to create its shape. The main drawback of a pressed deck is that they are made from thin gauge steel and do not have the same strength as fabricated decks.
The most noticeable benefit of a pressed deck is that they are significantly cheaper than fabricated decks. However, the downside to this cheaper manufacturing process is that pressed decks are much more likely to get damaged. Issues such as rust, dents caused by impact, and vibration can make a pressed deck unusable.
On the other hand, fabricated decks are significantly stronger as they are constructed of thick gauge steel and have welded joints. Even so, they are not immune and still face the same issues as pressed decks. For example, rust can still be an issue, as can impacts and vibration.
Rust can cause issues such as holes in your deck and eat away at pulley mounts and mounting systems. As for impacts and dents, you could run into issues such as blade obstruction and holes. Finally, vibration caused by the lawn mower usually loosens off bolts and fixings. So, not only will parts become loose and cause potential hazards, but they can also cause irreparable damage.
Inspect your deck for rust, dents, and loose fittings. If you find any damage on your deck, you’ll want to repair it right away. Check out my easy guide on how to repair a rusted lawn mower deck to fix surface rust and holes.
Deck Mounting System
When you look under your mower, you will find a series of metal hangers suspending your cutting deck. These are usually in the form of large bolts and brackets. If you closely inspect these brackets and bolts, you’ll see that they are designed to keep the deck level as it is lowered and raised by the mower’s height adjuster.
Unfortunately, any slight defect in the deck mounting system will affect the angle of the cut. Usually, you can adjust and level the deck, but this is only possible if everything is working correctly. So, broken bolts or damaged mounting points will result in an unevenly cut lawn. Also, if the deck mounting system is unable to function correctly, you may find that your cutting deck becomes stuck. Check out my article on how to fix a stuck riding mower deck to learn more about why this happens and how to fix it.
If you find damaged bolts or mounting points, the best thing to do is to replace them and relevel your cutting deck.
Pulley System
Most cutting decks have a series of pulleys that transfer the engine’s motion to the cutting blades via the deck belt. Unfortunately, a few things can go wrong with pulleys that will cause belts to break, pulleys to seize and come loose, and put stress on the engine.
So what do you need to look for?
The first thing to check is that the pulleys are securely fastened to your mower deck. Then, you want to inspect the pulleys for damage, such as bends or nicks in the flanges that could tear a belt. Finally, make sure that the pulleys and spindles can spin freely with the belt removed. If the pulley and spindles are hard to turn or they have some drag, then it will cause engine stress and premature belt wear, which are two potentially expensive repairs.
If you find a problem with the bearings, a loose pulley, or sharp edges on the pulleys, get your tools out and make the necessary repairs.
Idler Pulley System & Tensioner
The idler system puts tension on the belt so it can grip and slip as needed. To achieve this, your cutting deck has an idler pulley that sits against the belt and is tensioned by the tension spring.
The spring needs to be set to a specific tension to achieve the necessary grip. However, this can only happen if the idler pulley can pivot freely, the spring has sufficient recoil, and is adjusted correctly. The most common issue you’ll come across with the idler pulley system and the tensioner is that the spring is stretched out, and the pulley can’t pivot freely.
To check the idler pulley system, remove the belt and the tensioner spring, then check the movement of the pulley. Next, reinstall the belt and install the tension spring. Finally, use a belt tension gauge to check that your spring can achieve tension and that you have the tension set to the correct setting.
Grease Fittings
On the top of your cutting deck, you’ll find several grease fittings for injecting grease into the pulley spindles. These fittings allow you to keep the spindle bearings greased at all times without having to pull the bearings out.
You should find one grease fitting for each pulley and spindle set. First, check whether the grease or Zerks fittings are still in place. It is common for these fittings to get knocked off as they are very small and delicate. Next, inject the fittings with grease and check that they are working properly. Head over to my article on how to grease lawn mower spindles to learn more.
Protective Guards
The protective guards are the last item to check on your riding lawn mower deck. These guards serve two purposes. First, the protective guards protect you from the pulleys and belts while spinning at high speed. Second, they protect the pulleys and belts from damage.
Check that the protective guards are fastened securely and are not deformed. It is common for loose or misshapen guards to rub on the belt and cause it to wear down and eventually break. Also, make sure there isn’t any yard debris stuck underneath the guards. Again, debris can cause friction on the belt and pulleys and cause damage over time.
