Mower Tune-up Tips for Spring

May 16, 2022

Spring has finally made it! The weather has warmed up and maybe the spring rain has turned your lawn into a jungle. Whether you’ve put it off for as long as you could or you’ve been chomping at the bit all spring, it’s finally time to break out the mower and lay down a fresh cut on your lawn. Ask an expert or professional in the lawn care industry about the most important practice for achieving a dense, healthy lawn, and they’ll most likely say “frequent mowing”. We’re not going to debate how frequent “frequent mowing” is or discuss all of the benefits your lawn can reap from “frequent mowing”, instead, let’s talk about getting that mower tuned up so you have a reliable piece of equipment with which to perform your frequent mowing.

Is all this talk about frequency making you wonder how frequently you should perform a mower tune-up? Well, that depends on how much you're using your mower, commonly tracked as hours of use. Regardless of how many hours of use you rack up, make sure to inspect the items on the following list at least once per season. It will go a long way in maximizing the longevity of your investment in a lawn mower.

#1 Check Blade Sharpness

A good, sharp mower blade makes a big difference in the quality of the cut that your mower will deliver. Sharp mower blades cut the grass more efficiently than dull blades, which can reduce strain on your mower's engine and even save you some fuel. Sharp blades also reduce the stress placed on the grass from mowing by creating a clean, even cut that is faster to heal. Also, have you ever looked across the top of your lawn and noticed a dull, brown look on the tips of the grass blades? This can be from cutting your lawn with a dull blade that frayed your grass blades, resulting in a jagged wound on the leaf tip with brown, dead tissue still attached as the plant heals below the wound. How do you sharpen your mower blades? Read long to find out more!

If you’re using a rotary mower, meaning your blade spins around in a clock-like fashion, chopping the grass blades like an axe, you have it relatively easy as far as sharpening goes. People using reel mowers, meaning their blades are arranged in a cylindrical fashion and act like scissors clipping the grass blades against a bed knife, have quite a bit more work to do to ensure a proper cut. Assuming the vast majority of you are using rotary mowers, let’s focus on those in this article.

You can scour the internet and find a multitude of resources for various methods of sharpening your mower blade. Dremel tools, bench grinders, files, and tools made specifically for this purpose are the common methods you’re likely to find. Whatever method you decide to use, here are some things to keep in mind.

Always wear proper safety equipment. A good pair of gloves and a long-sleeve shirt will keep you from getting cut or burned by sparks. Also, eye and ear protection will protect your vision and hearing. Also, always disconnect the connection lead to your engine’s spark plug before getting anywhere near your mower blade.
Once the blade is removed, check to make sure that the blade is not cracked or bent, in which case it would be better to replace it.
Aim for your blade to be “butter-knife” sharp, we’re not looking to turn it into a samurai’s katana. The main thing is to smooth out any big nicks or abrasions on the blade’s face.
Once sharpened, check to make sure that your blade is balanced. Hang it from a nail and make sure it sits level, if it falls to one side, you need to continue grinding that side to remove more material. An unbalanced blade can place unnecessary strain on your mower engine and spindle that holds the blade in place.

#2 Inspect or Change the Air Filter

Air filters should be changed once per season or at the bare minimum, once every 300 hours of use. If your filter is equipped with a foam wrap or pre-filter, you can inspect that before every mow and make sure there are not any large chunks of grass or other materials on the surface, blocking the airflow. Clean air filters help your mower get the right amount of airflow into the engine, necessary for proper engine combustion. If you continue to use a clogged or dirty air filter, your engine will not run as efficiently and might even overheat. A clean air filter is a good insurance policy against costly mower repairs and can even reduce air pollution compared to a dirty filter. Make sure you replace your filter with the appropriate filter suggested by the manufacturer of your mower’s engine. This is a simple, cheap way to increase the life of your mower.

#3 Change the Oil

Engine oil should be changed every 25 hours or once every season. Some mowers claim the engine oil never has to be changed. In that case, make sure to at least check the level of engine oil before every mow to make sure you have the correct amount inside the engine. Too much oil can damage the seals in your engine and cause it to overheat or start to smoke. Too little oil can cause premature wear and tear on engine parts. Making sure to stay on top of oil changes and oil levels is a great way to extend the life of your mower.

#4 Inspect or Change the Spark Plug

Clean spark plugs are vital for proper lawn mower engine performance. They should be replaced or cleaned every 25-50 hours of mower use or at least once every year. Dirty spark plugs can cause your engine to misfire and also lead to increased fuel use, costing you more money to mow your lawn. Always check your mower manual or manufacturer’s website to determine the correct spark plug and gap width for your replacement. Changing them is relatively easy with a spark plug socket. Remove the electrical lead covering your spark plug. Once your spark plug is removed and before the new one is inserted, make sure to cover the open hole to make sure that dust or other contaminants don’t get inside your engine. Place your new spark plug in the engine the same way that the old one was oriented and tighten it down (not too tight!). Replace the electrical lead and you’re all set.

Additionally, always make sure you have fresh gas every season for your lawn mower. If your gas has been sitting in the can all winter, it may have been watered down by the ethanol in your gasoline drawing moisture out of the air all winter. Using bad gas can hurt your engine’s performance. So now it’s time to go tune up that mower before you begin the stripe show on the front lawn, regardless of how frequently you do it.