riding mower maintenance

Riding Lawn Mower Maintenance

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?

  • Full inspection
  • Oil & filter change
  • Air filter change
  • Fuel filter change
  • Spark plug change
  • Axle lube
  • Blade sharpen
  • Tyres 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 handy tune-up interval chart stuck under the hood or under the seat.

Topping Up Oil

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.

 

Knowing how to service and repair your own mower is a useful skill to have. Modern lawnmowers are DIY friendly and pretty simple really.

Info Chart


mower tune-up tools

Helpful charts are fitted to some mowers showing intervals and part numbers, however I've found the Husqvarna belt labeling to be wrong.

Ride-on mower engine sticker

Info Sticker

Helpful charts are fitted to some mowers showing intervals and part numbers, however I've found the Husqvarna belt labeling to be wrong.

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.

 

All tractor mower engines are very durable, and failures in my experience are rare and when they happen are 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 Engines

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. 

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 stabiliser at the end of the season, simply dump a can into a full tank of gas and run the engine a short while. Check out tractor mower winterising (internal link)

 

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".

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. 

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. 

Tools


mower tune-up tools

Briggs and Stratton, Kohler, Kawasaki, Honda. All engines are easy to work and no special tools are needed.

Tools

Wd40

1/4 & 3/8 Drive Socket Set

Selection of Wrenches

Selection of Screwdrivers

Torx Drivers

Pliers

Flat File

Wire Brush

Oil Catch

Air Pump

Gloves

Inspection Light

Ride-on mower engine tune-up tools

Tools

Briggs and Stratton, Kohler, Kawasaki, Honda. All engines are easy to work and no special tools are needed.

What Tune-up Parts Needed?

All engines will 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 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 for part numbers:

 

Briggs and Stratton specification

Honda specification

Kohler specification

Kawasaki specification

Id Your Engine

Kowing how to identify your mower engine is useful for parts ordering.


Ride-on mower tuneup kit Ride-on mower tuneup kit Ride-on mower id sticker Ride-on mower tuneup kit

Id Your Engine


riding mowerengine number riding mower engine number riding mower model number riding mower tuneup kit

Kowing how to identify your mower engine is useful for parts ordering. 

Inspection & Tune-up

In this guide I 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.

Engine Type


John Deere engine

Briggs and Stratton, Kohler, Kawasaki, Honda. All engines are very alike and easy to work on.

Ignition 


1 Plug Wire


Riding mower plug wire

Allow your engine to run for a couple of minutes before beginning the service, this thins the oil which helps the draining process. 

Always disable your mower before working on it. Remove plug wire and turn fuel off.

2 Plug


ride-on plug

Check that replacement plug is the same. Thread in new plug by hand before using the plug tool.

3 Replace


ride-on plug change

My father would say, "a cross thread is a tight thread"....not good. To avoid this, 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.

Ride-on mower engine

Engine 

Briggs and Stratton, Kohler, Kawasaki, Honda. All engines are very alike and easy to work on.

Ignition


1 Wire

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


Ride-on mower plug wire
Ride-on plug

2 Plug

Check that replacement plug is the same. Thread in new plug by hand before using the plug tool.

3 Replace

My father would say, "a cross thread is a tight thread"....not good. To avoid this, 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.


Ride-on mower plug wire

Lubrication


3 Drain

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


Ride-on mower oil drain
Ride-on oil filter

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.


Ride-on mower oil filter
Ride-on oil top up Ride-on oil top up chart

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.


Ride-on mower oil dipstick
Ride-on axle

Axle

All controls and levers will benefit from a spray of WD40.

Check rear axle oil level. The front Axle will have greasing points, for this you'll need a grease gun. 

Gas & Air


Ride-on gas filter

8 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.

9 Replace

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


Ride-on gas filters
Ride-on gas tank

10 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.

11 Air

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


Ride-on mower air filter

Blade Sharpening


Ride-on jack

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.

13 Deck

If your not comfortable working under your mower, then remove the deck.

Some decks will be pretty simple to remove.


Ride-on deck
Ride-on deck blades

14 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.

15 Flat

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

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


Ride-on mower blade
Ride-on oil blade

16 Bevel

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

17 Dress

Now dress the oposite side to remove the burrs. 

A sharp blade is the secret to a beautiful healthy lawn, and it extends the life of your mower.


Ride-on mower blade

Belt Inspection


Ride-on belt

19 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.

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.


Ride-on belt
Ride-on deck

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.


Ride-on mower blade
Ride-on oil belt cracks

Cracking

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

Deck Adjustment


Ride-on tyre pump

20 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.

21 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.


Ride-on deck level
Ride-on deck level

22 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.

23 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.


Ride-on deck
Ride-on deck level

Adjuster

Rear adjuster, wd40 helps.

Clean Cut

Decks that sag will impact your lawn causing damage to your blades and your lawn.

Want a professional clean cut? - Sharp blades and a level deck.


Ride-on deck level

Lubrication


4 Remove Drain


ride-on drain

Locate the oil drain. On most riding mowers the drain will be located on one or other side of the engine.

Have a suitable container to catch the waste oil. Some mowers are fitted with a handy oil drain pipe and clip.

5 Remove Oil Filter


ride-on filter

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 Oil Filter


ride-on filter

When fitting the new filter it is important to apply a light coat of engine oil to the oil filter seal, this prevents the seal distorting.

Tighten by hand only.

6 Add Engine Oil


ride-on add oil ride-on oil chart

Refit the oil drain plug. With the mower on level ground, fill with the correct oil type, to the full mark.


7 Check Oil Levels

ride-on oil check Grease axle

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.

If the engine has an oil filter, the engine will need to run for a minute in order to fill the new filter, then top up oil again as needed.

To run the mower turn on fuel and fit plug wire.

All controls and levers will benefit from a spray of WD40.

Check rear axle oil level, level indicator lives above the axle. The front Axle will have greasing points, for this you'll need a grease gun. 

Gas & Air


8 Remove Gas Filter


mower gas filter

From the bottom of the fuel tank you will find a fuel line. Check this line for cracks or leaks.

Next, replace the fuel filter, it will be between fuel tank and carburetor.

Usually you need only a square nose pliers to remove the fuel line clamps, twisting and pulling removes the old filter.

Some filters will be marked with an arrow - this points towards the carburetor.

9 Fit Gas Filter


gas filters

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

10 Clean Gas Tank


mower gas tank

Remove the fuel tank cap and check inside for dirt/grit as the outlet is very small and  blocks easily. If your unsure of fuel quality, drain it completely.

Depending on the amount of grit in the tank (every tank has some) you may need to remove it to clean.

I use a suction bottle and hose to suck the grit from the bottom of the tank and sometimes I have to remove it.

11 Air Filter


mower air filter

Remove the air filter and pre-filter, clean out the housing and cover taking care not to allow dirt drop into carburetor.

Replace or clean your air filter and pre-filter.

Blades


12 Jack Up Mower


riding mower 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.

13 Remove Deck


riding mower deck

If your not comfortable working under your mower, then remove the deck.

Some decks will be pretty simple to remove, others will be a challange. 

14 Removing Blades


riding mower blades

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.

15 File Flat


riding mower blade

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

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

16 File Bevel


riding mower blade sharpen

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

17 Dress the Blade


riding mower blade

Now dress the oposite side to remove the burrs. 

A sharp blade is the secret to a beautiful healthy lawn, and it extends the life of your mower.

Belts


19 Check


riding mower belt

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.

Glazed


riding mower belt

Things to look for are Blistering, glazing, cracking and fraying.

Cracked


riding mower brake

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

Flat Spot


riding mower belt

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.

Blistered


riding mower brake

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.

Deck


19 Pump Tires


riding mower tire 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.

Check Level


riding mower brake

Decks tend to drop at the front over time which will give an uneven cut, so lets go ahead and adjust it.

Place the mower on level ground and all tire pressures equal. Now measure the height of the four corners of your cutting deck.

Measure


riding mower deck

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

Adjust


riding mower deck

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.

Adjust


riding mower deck

Front adjuster, wd40 helps.

Clean Cut


riding mower deck

Decks that sag will impact your lawn causing damage to your blades and your lawn.

Want a professional clean cut? - Sharp blades and a level deck.

Related Questions

Should I run my lawn mower out of gas for winter? No, it is best to use a gas stabiliser, it keeps the gas fresh and will protect your fuel system. Running the gas out of the mower doesn't prevent gumming of the carburettor over winter.

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.

Auto Technician and Writer at | Website

John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.