Riding Lawn Mower Maintenance

Tractor maintenance chart

If you want a reliable mower all season, and who doesn’t? Then your Riding mower will need a tune-up at least once a year, preferable in the spring before the season starts. If you want a reliable mower all season, and who doesn’t? Then your Riding mower will need a tune-up at least once a year, preferable in the spring before the season starts.

So what is riding mower maintenance? To maintain a riding mower, the following components need attention:

  • Full mower inspection
  • Oil & filter change
  • Air filter change
  • Fuel filter change
  • Spark plug change
  • Axle lube
  • Blade sharpen
  • Tires pumped
  • Deck align
  • Throttle cable adjusted

At the very minimum the oil should be changed at the start of the season. If your mower is new, change the oil after the first 5 hours of use. Some mowers will have a useful tune-up interval chart stuck under the hood or under the seat.

Topping Up Oil

Oil dipstick check

Checking and topping up the oil is good practice but it’s not a substitute for an oil change. If your mower has an oil filter, change it when changing the oil, this is where all the contaminates are trapped.

Hood info chart

Info Sticker – Helpful charts are fitted to some mowers showing intervals and part numbers, however I’ve found the Husqvarna belt labelling to be wrong, just saying!

About Your Gas Engine

The 4 stroke single and v twin cylinder engines offered by B&S, Kohler, Kawasaki and Honda are all top drawer, and quality parts are easy to find. Your engine may be different to the demo models used in this guide, unless it’s a diesel, they’re all much similar. (see diesel engines below)
All tractor mower engines are very durable, failures in my experience are rare and when they happen, it’s usually associated with poor or low oil. That’s why checking your oil regularly and oil changes are so important. 

When To Tune-up Your Gas Engine?

When should I service? I advise my customers to service their mowers at the start of the season not at the end. Mowers that overwinter without being prepared usually suffer from gummed carburetor issues. You can avoid gumming by adding a gas stabilizer to the fuel system.

What Is Gas Stabilizer?

Gumming of small engine carburetors is a real problem. Over the winter months the old gas eats away at the inside of the carburetor. This is so common, and it’s so simple to prevent. Use a gas stabilizer at the end of the season, simply dump a few drops into a full tank of gas and run the engine a short while. See video her about mixing and adding gas stabilizer.
If your mower is running rough, changing the oil, plugs, air and fuel filter may not fix it. Gas mowers that run rough usually require carburetor cleaning. Check out “Carburetor troubleshooting”.

What Tools Are Needed?


A tune-up isn’t technical, and no special tools are needed. Like many tasks, it’s about the right knowledge and good preparation.

When it comes to tools, you don’t need top of the line kit, but do buy good quality tools, because good tools well cared for will last a lifetime. 


  • WD40
  • 1/4 & 3/8 Drive Socket Set
  • Selection of Wrenches
  • Selection of Screwdrivers
  • Torx Drivers
  • Pliers
  • Flat File
  • Wire Brush
  • Oil Catch
  • Oil filter tool
  • Air Pump
  • Gloves
  • Inspection Light
  • Grease gun

What Tune-up Parts Needed?

Engine number

All engines have a model code and date stamped somewhere. Briggs & Stratton stamp their codes into the metal valve cover at the front of the engine. Kohler have a tag and Honda have sticker on the body.

Tune up kit

Tune-Up Kits – Tune-up kits will include: plug(s); oil; oil filter (if fitted); air filter; fuel filter – everything you need. 

If your having trouble identifying your engine type, you can usually identify the right tune up kit by the shape of the air filter.

Check out your engine maker specs:

Briggs and Stratton tractor mower enginesOpens in a new tab.

Honda specificationOpens in a new tab.

Kohler specificationOpens in a new tab.

Kawasaki specificationOpens in a new tab.

Inspection & Tune-up

In this guide we will tune-up a single cylinder engine. In addition to a tune-up, it’s good practice to do an overall visual inspection. Mowers create a lot of vibration so look for any loose or damaged components, check rear axle oil, belts, pulleys, deck spindles, deck arms, battery connections, cables etc. Finding problems now is usually cheaper than them finding you later.

Your mower may not be the same as the demo model but that’s not important, the process will be close to identical no matter what model you have. 

Engine Makers

There are many different makes of mower and many are fitted with the very reliable Briggs & Stratton single cylinder engine. Kohler, Kawasaki, and Honda are also quite popular engines. All these engines are simple and easy to work on.

Tune-up Stepped Process

We’ll begin the tune-up process by starting and running the engine a while, just long enough to warm the engine oil. warm oil flows more freely and that helps remove more of the contaminates from the engine.


1 Wire – Remove the plug wire and leave it off until your ready to start the engine later in process.

Spark plug

2 Plug – Remove the old spark plug. To avoid cross threading, thread the new plug in by hand before using the plug tool.

Snug the plug down and give it a little tighten…. not too tight! don’t fit the plug wire just yet.


Oil drain

3 Drain – Drain the oil while the engine is still warm, this helps the draining process.

Oil filter tool

4 Remove – If you can’t find your oil filter, then you don’t have one, so you can go ahead and skip this part.

Remove the old filter, you may need an oil filter tool, but their usually not that tight.

5 Fit Filter – When fitting the new filter, apply some oil to the O-ring, it prevents distorting the seal when fitting. Only tighten the filter – hand tight.

Adding oil

6 Add Oil – If your mower has an oil filter, then check the oil level again after you test run the engine. This can be done at the end of the tune-up.


7 Check Levels – Add oil a little at a time, and check the level. Over filling is not good for the engine. It will cause oil leaks, misfiring and lots of smoke.


Grease gun

8 Check – Check rear axle oil level. The front Axle has greasing points, for this you’ll need a grease gun.

Air/Fuel System

Air filter

9 Air – Remove the air filter and clean the air box being careful not to allow dirt into the carburetor.

10 Remove – Gas filters are found on the gas line between the gas tank and the carburetor. If you have a gas tap fitted, it’s useful to turn it off before removing the old filter.

Gas filters may be directional, and if so will have an arrow which points to the carburetor.

Gas tank grit

11 Clean – Gas tank grit is common, I use a suction bottle and tube to remove it, and sometimes I have to remove the tank to clean it.

Blade Sharpening


12 Jack – Be sure to use an axle stand or block of wood to secure the mower as you’ll be working under it.

Don’t take any chances. Check out the tools on the blade maintenance page.


Deck – If your not comfortable working under your mower, then remove the deck. Most decks will be pretty simple to remove.

Balance – Removing deck blades for sharpening and balancing is best practice. Inspect the blades for damage, replace if bent cracked or worn. If the blades are in good condition, you can sharpen them in place.

13 Sharpen – Sharpening your blade is done with a good quality flat metal file.

Blade sharpening

Flat – Begin by dressing the face of the blade to remove any small nicks.

Blade sharpening

Bevel – Now we will file at the same angle as the bevel, some blades will have the bevel facing the other way.

Blade sharpening

Dress – Now dress the opposite side to remove the burrs. A sharp blade is the secret to a beautiful healthy lawn, and it extends the life of your mower.

Belt Check

14 Check – Check the condition of the belts. Most mowers have at least two belts, one for driving the mower and one for driving the blades. Some mowers will have more.

Mower drive belt

Flat Spot – These belts have a difficult job and can be the cause of various issues. Regular inspection will tell you if your belt is at the end of its life.

Blistering – Things to look for are flat-spotting, glazing, cracking and fraying.

Glazing – Worn or damaged belts cause slip, which in turn will cause vibration. The vibration can if ignored go on to cause lots of other issues.

Cracking – Better to take care of this now, waiting for it to break can cause other damage.

Deck Leveling

15 Pump – Check tire pressure and set to 1bar/15psi. Some customers like a lower pressure, and that’s okay, what’s important is that they’re all the same.


16 Level – Decks tend to drop at the front over time. Place the mower on level ground.

Measure the height of the four corners of your cutting deck.

Deck measure

Measure – Let your deck down approx. half way. Now measure the height of the four corners of your cutting deck.

Note the highest corner, and adjust all other corners up, so they match.

Deck adjusters

Adjust – You’ll find adjusters at each corner, they’ll have a lock nut that will need to be released first.

Turning these bolts adjusts the deck up and down. Spray with WD40 – makes life a little easier.

Clean Cut – Decks that sag will impact your lawn causing damage to your blades and your lawn. Keep your deck level and blades sharp, you’ll be rewarded with a healthy law and a healthy mower.

Diesel Engine Difference

Some manufacturers offer small diesel engines in their mowers, the main advantages are fuel efficiency and lots of torque. Mostly they’re fitted to the commercial range. Diesel engines tend to be very reliable, however when they fail they cost a lot more than a gas engine to repair.

Diesel Tune-Up

A service to a diesel engine will include: oil; oil filter; fuel filter; air filter. Doing an oil and filter change is just as important on a diesel. Note, if your changing a fuel filter on a diesel engine, the air will need to be purged from the system before starting the engine.

Purging Diesel Fuel System

Fill the new filter with fresh diesel before fitting. Then pump the primer, if installed on the machine. If you don’t have a primer – open the fuel lines at the injectors by about 2 turns, now crank over the engine until fuel spills from the fuel lines. Tighten up the lines and your good to go. If your diesel still won’t start after purging, then it needs to be purged again. 

Related Questions

Should I run my lawn mower out of gas for winter? Using a gas stabilizer is better than running a mower out of gas. Stabilizer will keep gas fresh and protect the fuel system over the winter months. Running the gas out of the mower doesn’t prevent gumming of the carburetor.

Can you store a lawn mower vertically? A lawn mower should be stored on its wheels, however if you drain the oil and gas from the engine you can store it in any position you like.