What to Do If the Lawn Mower Cuts Poorly: Top Problems and Solutions

You have a lawn mower — but not a clean cut. Instead of a neat trim, you get shredded grass, the engine stalls, or the machine won’t start at all. These issues are common among garden equipment owners. The good news? In most cases, the problem can be fixed without going to a service center — if you know what to check. This article covers the main reasons why a lawn mower cuts poorly and how to fix them yourself.

1. Dull or Damaged Blade

This is the most common reason for uneven cuts. A dull blade doesn’t cut — it tears the grass, leaving ragged edges that quickly turn yellow. Chips, cracks, or bends in the blade also cause vibration and overload the engine.

• Remove the blade and check for dullness or damage;
• Sharpen or replace it if needed;
• Replace the blade at least once per season with regular use.

2. Clogged Deck or Grass Build-Up

If the mower leaves streaks or doesn’t collect grass in the bag, check for a clogged cutting deck. Built-up grass, dust, and dirt can obstruct airflow, reducing suction and cutting quality.

• Turn off the engine and remove the battery or disconnect the spark plug;
• Clean the deck, shaft, and blade from dirt and grass;
• Wear gloves — the blade might still be sharp.

3. Starting Problems: Won’t Start or Stalls

If the lawn mower won’t start or stalls after starting, the issue may lie in the fuel or ignition system. Common causes include:

• Old or poor-quality fuel mix;
• Clogged fuel filter or carburetor;
• Worn or dirty spark plug;
• Clogged air filter disrupting airflow.

What to do:

• Drain old fuel and refill with fresh (especially after winter);
• Clean the filters and carburetor if necessary;
• Inspect the spark plug and replace it if worn or fouled;
• Clean or replace the air filter.

In many cases, simply changing the spark plug and refueling solves the startup issue in under 5 minutes.

4. Incorrect Cutting Height

Sometimes the issue isn’t mechanical — it’s a matter of settings. If the blade is too low, it hits the ground. If it’s too high, it misses the grass. This is especially common on uneven terrain. When choosing a lawn mower, pay attention to its cutting height adjustment range — the wider it is, the easier it is to adapt to your lawn’s needs.

• Adjust the cutting height via the wheel levers (usually 20–70 mm);
• For tall grass — mow in two passes;
• Don’t mow wet grass — it clumps and sticks to the blade.

5. Blade Drive or Belt Issues

If the blade isn’t spinning while the engine runs, the drive belt or clutch may be worn out. These issues often occur after 2–3 seasons of frequent use.

• Check the belt for wear and proper tension;
• Replace it if damaged (according to the mower model);
• Consult a technician if you’re unsure of the cause.

Maintenance Is Better Than Repair

To avoid problems, follow these basic care tips:

• Change the oil and filters as recommended by the manufacturer;
• Clean the mower after each use;
• Don’t store the machine with fuel during winter;
• Sharpen the blades regularly.

And most importantly — don’t ignore warning signs: if your lawn mower is stalling, hard to start, or the cut looks uneven, address the issue early. It saves time, money, and hassle.

Pro Tip: Always Inspect Before the First Cut of the Season

Before mowing for the first time in spring, inspect the mower’s key parts: blade sharpness, deck cleanliness, oil level, and fuel. Just 5–10 minutes of attention can prevent serious issues and extend the mower’s lifespan.