How Do You Start A Lawn Mower?

Starting a mower is a straight forward procedure. But before you start your mower, it's always a good idea to check the fuel and oil level.

Do a quick check over, looking for any loose or damaged parts. Turn the mower over, carburetor side up, and check for grass build up and blade condition.

How do you start a lawn mower? To start a lawn mower successfully you need to:

Check oil level
Check gas level
Gas tap on (if fitted)
Choke on (if fitted)
Bail lever on
Pull cord sharply

In my experience, many non starts are caused by a simple issue, something a home owner can easily take care of.

This post should have you covered, but if you need video help check out “Common causes of a no start mower video”.

It walks you through the lawn mower starting process and how to check all the common simple causes of a no start mower.

Oil Check

Oil is best checked on a cold engine, I check the oil level every time I fill the gas tank. Most mowers will be happy with 10w30 car engine oil and from empty, take about .65 of a quart (.6lt).

Why not go ahead and give your mower a tune-up, a lawn mower should be serviced at least once a year. The beginning of the new season is the best time to tune-up your mower.

This guide will help you service your mower in under an hour – ” Lawn mower tune-up”.

Fuel Check

If this is the first start of the season, consider the fuel quality. Gas that’s been in the mower since last year is probably bad. So if your mower is hard to start or won’t start – try draining the gas tank and filling with fresh gas. If the problem persists then a carburetor clean will fix the gremlins.

This easy to follow guide will walk you through the whole process – “Carburetor cleaning”.

Fuel Stabilizer

Last seasons gas is the number one reason for lawnmower no starts. We all do it – put the mower away, not knowing for sure if that was the last cut. Before you know it, it’s spring and guess what? The mower won’t start, now you’ll need to clean out the fuel system.

To prevent this happening next spring – at the end of this season, buy some fuel stabilizer, mixed with the gas, it’ll keep it fresh for up to 2 years, so next spring it’s pull and mow.

I use Sta-bil gas treatment,1 ounce treats up to 2.5 gallons, it prevents gumming and cleans the fuel system. It can be used in all gas powered kit including 2 stroke engines. You can check the price of Sta-bil on Amazon.

Check Oil

Best to check the oil before starting the engine.

A low oil level will often prevent the engine from starting.

Add Oil

Add small amounts and then check.

Too much oil is almost as bad as too little.

What Is A Choke?

The Function of a choke or priming bulb is to enrich the fuel mixture, so a cold engine starts smoothly. Gas engines run best when the ratio of air to fuel is 14.7 to 1. Meaning 14.7 parts air to 1 part fuel, also known as air fuel ratio (AFR).

Using the choke or priming bulb enriches the fuel mixture which counteracts the lean condition caused by the dense cold air. Engine manufactures commonly use two system types to achieve smooth cold starts.

Choke Plate

The Choke Plate type, usually controlled by a lever. Some of the latest choke plates are thermostatically operated meaning they are an automatic system. This choke plate reduces the amount of air and increases the amount of fuel supplied to the engine.

Primer Bulb

The second type is the Primer bulb. This is very simple and easy to use, it creates a fuel rich condition by squirting extra fuel into the engine. You do this by pressing a rubber primer bulb, mounted at the carburetor

Choke

Choke set to full to start a cold engine, after the engine warms up move the choke to the fast setting.

Some mowers use a snow flake symbol for choke.

Primer

If your mower doesn't have a choke lever, then it may have a priming bulb.

If so pressing 3 times primes the engine with enough gas to start.

Simple Starting Procedure

First pick a suitable location to start your mower, you don't want tall grass catching the blade as your trying to pull start the mower. If you have a throttle lever type system go ahead and move the lever to full choke. If you have the primer bulb type, press three times.

Choke

If you have a throttle lever type system go ahead and move the lever to full choke. If you have the primer bulb type, press three times.

Bail Lever

Now hold the Bail lever also known as the dead man's lever, this is the bar at the top of the handle bars usually marked with a stop symbol. The Bail lever is a safety feature which modern mowers must have. Its function is to stop the blade from spinning and kill the engine within 3 seconds of bail lever activation.

Pull Cord

Now grab the pull cord handle and give it a good yank, the engine must turn over at 350 rpm minimum in order to produce a spark strong enough to ignite the fuel. If you find the pull cord very stiff to pull, make sure the blade isn't obstructed by dry grass on the deck, and check that the bail lever is working properly.

Try Again

Most mowers don't run with the first pull so don't be disappointed. It may take two or three pulls. If it takes more than three pulls you may flood the engine with too much fuel. If this happens, just leave it sit for thirty minutes and try again, but this time don't apply choke.

After Starting

As soon as your engine has warmed up, move the throttle lever to fast/run (If manual choke fitted). A warm engine ran continually on choke will give off black smoke, run poorly and will shorten its life.