How to Adjust the Deck on an MTD Riding Lawnmower

An uneven cut lawn is more unsightly than an overgrown one. Through normal use and time, an MTD mower deck often becomes uneven, leaving an awkward looking swath of grass behind it. But, adjusting the mower deck will level out and result in an even cut.

Crescent wrench

Pliers

Tape measure

Combination wrench

Position the MTD mower on a surface that is level, firm and provides adequate room to work. Raise the mower deck height to its highest position and remove the spark plug cable from the engine to avoid accidental starts.

Rotate the mower blades by hand in a parallel position with the mower. Wearing gloves when handling mower blades is always a good idea. With the blades in position, measure the distance from the front tip of each blade to the ground. Do the same for the rear tip of the blade. Note the measurements on a piece of scrap paper or notebook.

The difference between the front and rear measurement is ideally between 1/8 and 3/8 inch, with the front being slightly higher than the rear, according to the MTD owner's manual for a 7600 riding mower.

Rotate the blades 180 degrees and take the same two measurements to the ground. If the blade is straight, the measurements will be the same as before. If the measurements are different, double check the measurements again to make sure the first ones were accurately taken. If the first pair of measurements differ from the second, the blade is bent and needs replacement.

If they are straight, adjust the front deck height to bring the measurements within specification.

Loosen the jam-nut on the stabilizer bracket on the front of the mower deck. The stabilizer looks similar to an L, and pins to a welded bracket on top of the leading edge of the mower deck. Loosening the jam nut will allow for the deck to adjust higher, or lower, depending on the need.

Tighten the locknut to raise the leading edge of the mower deck, or loosen the nut to lower it. Turn the locknut with a crescent wrench once the jam-nut is loose. Remeasure the distance from the front and rear of the blade to ground to check the adjustment. Once achieving the proper height, retighten the jam-nut to secure the stabilizer into place.

With the mower deck raised to its highest setting, rotate the blades perpendicular to the lawn mower. Measure the distance between the outside edge of the left blade to ground. Repeat the measurement on the right side blade. The distance from the edge of the blade to ground should be the same on both sides. If one side is lower than the other, raise the low side of the mower deck to equal the other side.

Loosen the hex-head nut on the deck hanger. There is a deck hanger on each side of the mower deck, just in front of the rear wheel. With the hex-nut loose, adjust the deck height by turning the gear adjustment behind the deck hanger. A combination wrench provides the best control for adjusting the gear. Turn the gear clockwise to raise the mower deck. Measure the blade distance to ground after each turn to check for proper height.

Tighten the deck hanger hex-head nut with the crescent wrench when the deck is level. Double-check the adjustments on both sides of the lawn mower to ensure everything is tight.

A bent mower blade exhibits similar symptoms to an unlevel mower deck.

Check the mower height adjustment after replacing the blades or drive belt.

Wear gloves when handling mower blades.

Disconnect the spark plug cable before performing maintenance or adjustments to the lawn mower.