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How to Install Riding Lawnmower Blades, step by step

Is your lawnmower giving irregular cutting patterns across the garden? Does it seem to cut worse than before? Well, if you’re a homeowner and love keeping your garden neat and elegant, this situation might not be ideal for you. To diagnose this problem, it is a good idea to start by inspecting your mower’s cutting blades first. Damaged cutting edges indicate the need for a blade replacement. If you haven’t performed blade maintenance before, there’s no need to worry. This article lists all the steps needed to replace and install a new set of cutting blades on your riding lawnmower.

How to install riding lawn mower blades, step by step:

  • Step 1: Disengage the blade lever and lower the mower deck. Disconnect the spark plug cables
  • Step 2: Depending on your situation detach the mower deck by removing the connections with the mower’s frame
  • Step 3: Tilt the deck over to view the blades. Detach the blades entirely by unscrewing the nut
  • Step 4: Assemble the new cutting blades in a correct orientation. Tighten the nut to secure it firmly
  • Step 5: Reassemble the mower deck back and start your lawnmower

The blades on any lawnmower are situated underneath the mowing deck. Most riding lawn mowers come with a second set of cutting blades. The general direction of rotation of blades is anticlockwise. Most homeowners tend to sharpen or replace their blades annually. However, if you notice a drop in your lawnmower’s cutting performance, a blade replacement might be on the cards. Prolonged use on rough, rocky services can increase blade wear and raise the instances of bade replacement.

To further elaborate on the steps mentioned above, we recommend that you keep reading this article as it uncovers some useful information that shall resolve your problem.

Installing Riding Lawnmower Blades, step-by-step:

Installing new riding lawnmower blades is not a difficult job. Just follow the needed steps:

● Equipment needed:

To perform this task, you need:

  • A wrench set
  • A wooden block
  • Leather gloves
  • New cutting blades

Step 1: Perform the initial measures:

Before replacing the blade, we first need to prepare the mower by performing some initial steps as precautionary measures.

– Remove the ignition key:

To start, you should turn off the ignition switch in your lawnmower by removing the key from it. Also, engage the parking brakes.

– Disconnect the spark plug cables:

Next, you need to raise the hood of your riding lawnmower to access the engine. Disconnect the spark plug cables. This step is done to ensure that your lawnmower doesn’t accidentally start while performing the repairs.

Step 2: Remove the mower deck:

The cutting blades are located underneath the mower deck. You can access the blades by tilting or raising the mower. As a riding lawnmower is really heavy this is often not easy. One of the solutions is to use a lawnmower lift. Another method is to remove the mower deck. If you’re a beginner this step might seem technical, but it turns out to be relatively easy if you follow the steps below.

– Lower the mower deck:

The first step is to lower the mower deck to its lowest position by pushing the lever located above your rear left wheel. Next, you need to pull the blade engagement lever back to disengage the cutting blades.

– Roll the belt off from the engine pulley:

The blade belt transfers power from the engine to the blades. You should slide it off from the engine pulley and the belt keepers before you begin removing the mower deck.

– Take the mower deck off:

The following components need to be removed for detaching the deck entirely from the mower’s frame.

1. Front lift link support:

This linkage connects the deck’s front side to the mower’s body. To remove this support, remove the retaining pin and the washer at the joint. Then detach the lift link support from the mower deck.

2. Suspension arms:

The suspension arms connect each side of the mower deck from the middle to the mower’s frame. They can be detached by removing their retaining clips. The arms from both the right and left sides should be detached.

3. Rear deck bracket:

This support makes a connection between the deck’s rear end and the mower’s frame, just like the lift link support at the front. Remove the washers and the retaining clips that connect this bracket to the deck. With those removed, the deck is now free from mechanical connections with the mower’s frame.

Move the deck out from underneath the mower to access the blade cable.

– Detach the blade cable:

The blade cable controls the blade’s engagement with the ground via a pulley. You can use nose pliers to pull the cable out from its mounting brackets. You might see a blade cable spring whose one end is connected to the idler pulley’s arm. You need to detach this spring from the idler arm and put the cable aside.

Now, we shall proceed to the removal and installation of the lawnmower cutting blade.

Step 3: Remove the existing blade:

With the mower deck removed, flip it over to view the cutting blades. Now, to remove the existing blade, you might need to place a wooden block at the side of the blade to prevent it from spinning while you loosen its nut. Check how to current blade is attached, so you know what side should be up when you attach the new one.

Use the wrench to turn the nut counterclockwise (for loosening) with the blade locked via a wooden block. After the bolt is removed, detach the old blade entirely from the deck.

Step 4: Assemble the new cutting blade:

We recommend going through your owner’s manual to get detailed instructions regarding some specifics of your device. Always purchase the cutting blades as per your manufacturer’s recommendations.

– Fixing the new blade:

For fixing the new blade, the placement of the right side is very crucial. Most blades have the grass side and the mower side mentioned on them. But in case it isn’t, you should note the side at which the cutting edges are lowered more towards the ground is the correct placement.


Note that incorrect installment of the cutting blades can affect your cutting grass and is also detrimental to the lawnmower’s service life. In worst-case scenarios, you might be looking at a bent crankshaft if the blades are incorrectly installed.

– Tighten the blade:

After the correct placement is determined, place the bolt back to secure the cutting blades. Again, use a wooden block to prevent the blade from spinning while tightening it with a wrench. For tightening, you need to rotate the wrench clockwise.

Step 5: Reassemble everything:

When the cutting blade is installed, reassemble the removed parts starting with the blade cable spring. Reassemble the deck by connecting all its linkages in the same manner while it was disassembled. Reconnect the spark plug wire. Start your lawnmower and notice the improved cutting performance with the new blades.

Related Questions:

1. Which way do the blades go on a riding lawnmower?

There are two methods of determining the blade orientation on any lawnmower:

– Method 1: The sharp edge aligns with the rotation:

In this step, the blade’s sharpest side is considered and is made to align with the direction of rotation of the drive shaft. The sharp edge must point towards the drive shaft’s rotation. Generally, the drive shaft rotates in an anticlockwise direction. But if it is unknown, you might need to start your mower to check for the direction of rotation.

– Method 2: The bent edge pointing towards the mower’s body:

A relatively easy method is to consider the blade edge opposite to the sharpened edge. This edge has a bent towards one side. You should be sure that the blade is aligned so that this bent edge points towards the lawnmower’s body.

2. Why does my mower cut uneven?

If your mower is cutting uneven patterns of grass, there can be several solutions possible.

  • Stair-shaped patterns: If the grass patterns indicate a stair-shaped profile, like being raised at one end and lowered at the other, this is due to the incorrect level of the mower deck. This effect may be due to insufficient tire pressure at one side or incorrect adjustment.
  • Strips of alternating height: If the grass patterns show an alternating height trend, that may be due to a very fast mowing speed. To fix this, you should pull the throttle lever back.
  • Ragged cutting edges: If the grass edges appear ragged or uneven instead of smooth, that is due to cutting edges of the blade that have become blunt and need sharpening.
  • Blade vibration: Blade vibration can also be a cause of uneven cuts. The vibration may be due to a play in the nut that connects the blade. Also, worn out idler pulleys and the belt may cause vibrations in the blade that can contribute to uneven cuts.

3. Why does my lawnmower leave a row of grass between blades?

If you see a row of uncut grass patterns, then your blades might need sharpening. You can sharpen the blade’s cutting edge using a bench grinder. Also, incorrectly installed blades and a high mowing speed might be causing the issue. Make sure the placement of the blade is correct.

Final Remarks:

Installing the lawnmower blades might seem a tricky task. Still, it can be performed with sufficient ease by following the steps mentioned. It would be best if you replaced your cutting blades at the start of the season to maximize the cutting efficiency. Always keep a check on the blade condition as it helps to determine whether you need a replacement or not. In some cases, only sharpening is needed with a grinder, and you are good to go. If their ends appear damaged, consider replacing them. Always be careful while handling the blades to avoid cuts to your skin.