Here’s why this happens and what you can do: Dirty Air Filter on Your Lawn Mower: Clean or replace. Dirty Spark Plug: Clean or replace. Build Up of Clippings & Debris: Clean underside of your lawn mower deck as noted above.
If your freshly mowed lawn looks like it’s been cut to different heights, it’s a sign that your battery lawn mower blades might be blunt. The areas of bluntness and sharpness on the blade is what makes the grass appear it has been cut at varying heights.
Sharpening or replacing the mower blades is also the answer if grass tips look ragged or tattered instead of cleanly cut. Blade vibration also causes an uneven cut. To eliminate vibration, replace unbalanced blades and worn mandrels.