Tune Up a Lawn Mower

Home > DIY Projects > Car & Truck > Oil Change > Tune Up a Lawn Mower

Save
X
Log in to My Account

Log in to enjoy membership benefits from The Family Handyman.

Email Address

Password

Remember me on this computer

Forgot your password?

Don’t have an account yet?

Sign up today for FREE and become part of The Family Handyman community of DIYers.

Member benefits:

Get a FREE Traditional Bookcase Project Plan

Sign up for FREE DIY newsletters

Save projects to your project binder

Ask and answer questions in our DIY Forums

Share comments on DIY Projects and more!
Join Us Today

User Comments
Write a comment about this project
+ Add Your Comment

Tune your lawn mower in 3 easy steps. It'll run better, last longer and burn fuel more efficiently and cleanly.

By the DIY experts of The Family Handyman Magazine

TIME
Instant!
[+] View details

close X

TIME
Instant!
[–] Hide details

Allow about 1/2 hr.

COMPLEXITY
Simple
[+] View details

close X

COMPLEXITY
Simple
[–] Hide details

You only need a screwdriver and a spark plug wrench.

COST
Under $20
[+] View details

close X

COST
Under $20
[–] Hide details

All new materials—spark plugs, oil and an air filter—cost less than $15.

Step-by-Step

Change the oil and air filter

1 of 1

Photo 1: Change the oil and filter

Loosen the air filter cover screw and drop the cover down. Pull out the old air filter and press in the new one (make sure the paper pleats are facing out). Replace the cover and firmly tighten the cover screw.

It's just plain smart to tune up your lawn mower every spring. According to manufacturer Briggs & Stratton, a tune-up can increase fuel economy by a third, extend the life of the engine, reduce repair costs and decrease emissions by up to 50 percent.

The three main components involved in a mower tune-up are the air filter, spark plug and oil, all of which must be changed. The needed parts and supplies can be found at home centers and hardware stores.

Start by changing the oil. Run the engine for a few minutes to warm up the oil so it'll drain better. Stop the engine, remove the drain plug and empty the old oil (tilt the mower back to get it all out, if necessary). Replace the drain plug and fill the mower with oil until it's visible through the oil fill hole, or check the level on the dipstick, if so equipped.

A clean air filter helps maintain the proper fuel/air ratio, allowing the mower to burn less gas. Swap out the old air filter (Photo 1).

Replace the spark plug

1 of 2

Photo 2: Install a new spark plug

Pull off the spark plug wire and remove the old plug with a spark plug wrench or deep socket (13/16 in. or 3/4 in., typically). Hand-turn the new plug until the threads catch. Ratchet the plug down until it stops, then turn it another quarter turn (cranking down too hard can break the plug or render it nearly impossible to remove).

The new plug should come with a proper size gap.

2 of 2

Photo 2A: Close-up of spark plugs

The new plug should come with a proper size gap.

« Previous Photo Next Photo »

Next, remove and replace the spark plug (Photo 2). If the plug's rusted tight, spray it with a penetrating lubricant like Liquid Wrench or JB80. Let it soak in for 10 minutes before trying to loosen the plug again.

The spark plug will be factory gapped, but make sure there is a gap between the electrode and overhanging arm. If you drop the plug and the overhanging arm bends tight to the electrode, the mower won't start.

Tools & Materials

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

Socket/ratchet set
4-in-1 screwdriver

You'll also need a spark plug socket.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

Air cleaner
Engine oil
Spark plug

Shopping List

Tune Up a Lawn Mower - Shopping List

Comments

Comments from DIY Community Members

Share what's on your mind and see what other DIYers are thinking about.

1 - 6 of 6 comments

Show per page: 20 All

Sort by: Newest First Oldest First

+ Add Your Comment

texasjpe

March 18, 12:40 AM [GMT -5]

on self propelled mowers, the self propel hardware usually blocks or covers up the oil drain plug on the underside of the deck/engine. easier to just drain the oil out through the oil dipstick tube by tilting the mower on it's side. will give the same result as far as changing the oil. also it is best to use 30 weight oil. 10w30 oil sometimes especially in the southern states will cause engine to run too hot and will make it hard to start when hot. 30 weight does a lot better protection agains heat in the southern states. I am sure 10w30 will do fine in the cooler climates . -thanks.

wmartinusa

July 21, 7:05 PM [GMT -5]

1. Place a dab of dielectric grease on the spark plug tip (tip only) before replacing the wire. (dielectric is right. in grease it means it aligns with current, not insulates)
2. Use auto wheel cleaner over the entire mower, only when cool, and hose it off strongly; you'd be amazed at the nooks and crannies that get filled with dirt/gunk. (Stuff that will keep it from running next spring). Putting a plastic bag over the air intake won't hurt.
3. Since cleaning a carb correctly is beyond this, if the machine is more than 2 seasons old, run some carb cleaner in the next tank of gas. Get the proportions right.
4. Buy a little blade sharpener (drill or manual) at the big box stores and touch up your blades. They'll last much longer. (disconnect the plug. AND BLOCK THE BLADE WITH A PIECE OF WOOD; you do that by jamming the blade and the wood piece where they can't move.)
5. Lubricate your cables. Seriously. They stretch less and will delay a tune up. Pour some very lightweight oil (NOT WD40) into the top ends; a piece of duct tape will make a good funnel, just keep the sticky side out.

The-family-butler

July 07, 5:08 PM [GMT -5]

when tuning up a lawn mower, never spray wd40 unless you plan on hosing off mower. I did it once and nearly caught a tractor on fire.

JDAWG

June 22, 6:00 PM [GMT -5]

Spark plug wire should be disconnected before working under mower

JDAWG

June 22, 5:58 PM [GMT -5]

Spark plug wire should be disconnected before working under mower

JDAWG

June 22, 5:58 PM [GMT -5]

Spark plug wire should be disconnected before working under mower

+ Add Your Comment

closeX