Commercial Lawn Mower Repair & Maintenance Tips

Keep your riding mower or walk behind mower running strong all season long.

Like anything with hundreds of moving parts, a lawn mower may require attention now and then. It may be gas related engine starting problems or lawn cutting issues due to natural wear and tear.

While we recommend you trust your local authorized dealer for lawn mower repair and maintenance, sometimes it's a simple fix (or one that requires immediate attention). You may not have a storeroom filled with lawn mower parts, but chances are you have a few essential tools and a good deal of self assurance.

Before we go into some of the common repairs you can do yourself:

  • Read your entire operator's manual to understand your machine and the safety warnings. Many of the procedures explained in this article require and understanding of basic procedures that vary between lawn mower models.
  • Never attempt a repair while the blades are running or the transmission is engaged.
  • Refer the repair to an expert if you find yourself unsure of how to proceed.

Lawn Mower Engine Starting Problems

Today's engines are marvels of technology. This makes them as reliable as they are complex. Some problems don't require training in small engine repair and can be addressed in the field.

Fuel-Related Mower Engine Issues

If your lawnmower won't start, is difficult to start, runs rough or exhibits a lack of power, it could be due to your gasoline or other fuel if so equipped.

Check the quality of fuel you are buying. Most gas engines are designed to work with a maximum E10-rated (10 percent ethanol) fuel. Higher percentages of ethanol can cause premature engine failure. Gas that has been sitting for several months can also create starting problems. If you suspect it's your gasoline, drain the fuel tank and fill it with fresh fuel.

If that doesn't solve the problem, clean the carburetor (if so equipped). Try a canned carburetor cleaner first. Remove the air cleaner and use the product as directed by its manufacturer. If this doesn't solve the problem, manually clean the carburetor.

Electrical-Related Mower Engine Issues

Check all fuses and replace any that have blown.

Test your lawn mower battery for appropriate power. The battery should be putting out a minimum of 12 volts. Check for loose or corroded battery connections. Tighten battery clamps and clean the terminals if necessary.

Check for loose or corroded electrical connections as well as frayed or broken wires. A frayed wire can be dangerous, and it may not deliver the full amount of power required by the system it's connected to.

Finally, check all spark plugs and replace if needed.

Lawn Cut Quality Problems

For general lawn cut quality issues, clean the underside of the lawn mower's cutting deck. Use a scraper to remove accumulated grass clippings, which tend to form a solid crust. Clean the top side of the deck, as well.

Uneven Lawn Cut

If your lawn mower is cutting lower on one side, check your tire pressure in all tires. Follow your manual's inflation recommendation, as this varies based upon mower weight and other factors.

Measure all three blades (height from blade tip to ground) while your lawn mower is on a level surface. If the heights are not equal, adjust the deck shell accordingly.

Inconsistent Quality Lawn Cut

If you are noticing uncut spots, stringers or discharge problems, this can be due to dull, bent or broken blades. Inspect the lawn mower blades and sharpen or replace them as needed.

Check belt tension for proper spring adjustment. Check for any obstructions either above or below the deck. Ensure the deck is level.

Check the engine RPMs using a tachometer. Inconsistent RPMs will affect cut quality.

If all the above suggestions check out, there is one more trick up our sleeve. You will find a removable baffle at the rear of the discharge chute. Remove the two bolts fastening it to the mower and the triangular plate should come right off. Save this assembly; as when the grass is dryer (in hot months), you will want to reinstall it.

Lawn Mower Tire and Traction Issues

If your lawn mower tires are slipping, check that the inflation matches what is recommended in the operator's manual. Also examine your tire treads for wear. Worn tires should be replaced as soon as possible for safe operation.

Regular Lawn Mower Maintenance

Wash the unit as often as practical. Be sure to cover all electrical components to protect them from water infiltration. After washing, dry the lawn mower and grease all fittings. Compressed air or a leaf blower helps dry the mower parts and crevasses that are difficult to access with towels and rags.

Store your mower indoors (a shed or garage) when not in use. Sun prematurely damages parts, and inclement weather accelerates the formation of rust.

Check oil before each day's use. Visually inspect all belts, tires and the overall machine for loose nuts and bolts.

If the lawn mower will sit for an extended period, such as during winter, disconnect the battery cables, remove the battery and store it in a warm place and/or use battery tender to maintain its charge.

Periodic Lawn Mower Maintenance

Every 25 hours

  • Clean deck
  • Check blades
  • Lubricate/grease unit
  • Check tire pressure for cuts and wear
  • Check/clean engine cooling fins and intake

Every 50 hours

Every 100 hours

  • Check mower blade stopping time
  • Clean battery cables
  • Initial change of hydro oil

Every 400 hours

  • Service hydraulics (replace filter, inspect and replenish fluid)
  • Winter storage
  • Clean underside of deck and lubricate (spray with WD-40 or equivalent)
  • Fuel stabilizer