Level Your Tractor Mower Deck

SKILL LEVEL 2

You love your tractor mower – it makes it easier to care for your large lawn and has that big-toy appeal. If your cut seems a little choppy and uneven lately, it's time to check the levelness of the mower deck that supports the blades. In less than half an hour, you can measure and adjust the front-to-back and side-to-side alignment of the mower deck.

2 Skill level
2 out of 5
6 Steps
5 Materials

Step 1 Prepare the mower

Before you start leveling your mower deck, review the safety instructions in the product manual.
Park the mower on a level, paved surface and inflate all tires to the recommended pressure marked on the tire. That way, any unevenness you find is in the mower deck to which the blades are attached, not the ground or tires.

Move the attachment lever to the highest position, disengage the mower, turn off the ignition and set the parking brake. For safety, remove the key from the ignition. You can remove the spark plug to ensure that the mower can't accidentally start.
Step 2 Check the side-to-side levelness

Put on heavy work gloves, and then lift the plastic blade guard and carefully rotate the blades so they form one line from side to side. Measure the distance between the pavement and the bottom of the outer end of each blade. If the difference is more than 1/8 inch, the mower deck needs a side-to-side (horizontal) adjustment.
Step 3 Make the side-to-side adjustment

Locate the lift link locknut on the angled bar in front of the left rear wheel. Use a wrench to turn it clockwise if your measurements showed that the right side of the mower deck is higher than the left; turn it counterclockwise if the left side is higher than the right. Each full turn changes the mower deck height by about 3/16 inch.
Measure the distance from the blade ends to the ground again and adjust the locknut until the difference is no more than 1/8 inch.
Step 4 Check the front-to-back levelness

Carefully rotate the blades so they are parallel to the sides of the mower and to each other. Measure the distance between the pavement and the front end of one of the blades. Repeat for the back end of the same blade. For best mowing results, the front end should be between 1/8 inch and 1/2 inch lower than the back end. If it's outside that range, the mower deck needs a front-to-back (vertical) adjustment.
Step 5 Make the front-to-back adjustment

Locate the jam nut at the front of the mower, centered between the front wheels. Use a wrench to loosen it enough that you can move the adjustment nut behind it. Turn the adjustment nut clockwise to raise the front of the mower deck or counterclockwise to lower it. Each full turn changes the height about 1/8 inch.
Measure the distance from the blade end to the ground again and adjust the nut until the front end of the blade is between 1/8 inch and 1/2 inch lower than the back end.
Step 6 Inspect and test

Inspect all pulley guards and deflectors attached to the mower deck to make sure they are in good condition and securely attached.
Replace the spark plug if you removed it. Then start the mower and mow a section of lawn to make sure the cut is even.