Starting a mower is a straightforward procedure. But before you start your mower, it’s always a good idea to check the fuel and oil levels. 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 lawnmower? To start a lawnmower 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 nonstarts are caused by a simple issue, something a homeowner 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”. The video walks you through the lawnmower starting process and how to check all the common simple causes of a no-start mower.
Simple Starting Procedure
First, pick a suitable location to start your mower. You don’t want tall grass catching the blade as your try 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.
1 Check Oil – Best to check the oil before starting the engine. A low oil level will often prevent the engine from starting. The upper mark is the correct oil level. Check out this guide to help check oil level.
2 Gas – Is there enough gas in the tank? A low gas level may cause hard starting.
3 Gas “On” – Gas valves are not fitted to all mowers. They are used to stop the flow of gas to the carburetor. The gas tap should be turned off when the mower is in storage. Click here for help finding your gas tap.
4 Choke – If you have a throttle lever-type system go ahead and move the lever to full choke.
If you have an Auto choke, you can go straight to yanking on the pull cord.
Primer bulb – Your mower may have a primer instead of a choke lever. If so press it 3 times.
5 Bail Lever – Now hold the Bail lever also known as the dead man’s lever, this is the bar at the top of the handlebars usually marked with a stop symbol. The other lever is the self propel lever.
The Bail lever is a safety feature that 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 to sit for thirty minutes and try again, but this time don’t apply the choke.
Or check out the flooding video here.
6 After Starting – As soon as your engine has warmed up, move the throttle lever to fast/run (If manual choke fitted). A warm engine running continually on a choke will give off black smoke, run poorly, and will shorten its life.
Oil Check & Adding Oil
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 lawnmower 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”.
Add Oil – Add small amounts and then check. Too much oil is almost as bad as too little.
Common Lawn Mower Fuel Problem
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 it 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 season’s 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 from happening next spring – add a stabilizer to the gas before the season’s end. 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. Check out the video on fuel stabilizers, it covers mixing and adding.
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 an 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 manufacturers 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 snowflake symbol for the choke.
How can I start my pull-start lawnmower if I’m not strong enough to use the starter cord? You can tune up your engine and adjust the valve lash, this will reduce the amount of strength needed to turn over and start the mower. In addition, have a starter motor and battery fitted.
How to start a lawnmower in one pull? To start a mower in one pull, make sure your gas is fresh, prime the engine, put the bail lever on, and now one good pull.
- About the Author
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John Cunningham is an Automotive Technician and writer at Lawnmowerfixed.com.
He’s been a mechanic for over twenty-five years and shares his know-how and hands-on experience in our DIY repair guides.
Johns’s fluff-free How-to guides help homeowners fix lawnmowers, tractor mowers, chainsaws, leaf blowers, power washers, generators, snow blowers, and more.