Last Updated on August 8, 2021 by woodcutter
I’m sure you have done a tone of research on how to start a lawn mower that has been sitting? If you have used one of these machines for landscaping like I have done so for years, you may say it is as easy as ABC. However, to cater to first-time users, I shall not leave any stone unturned so that you will be able to run your mowers in no time.
Mowers come in different types, which is electrical and petrol/gasoline type, and it is just a matter of switching on the power button or pulling a chord to get the engine running. However, problems arise when your much-loved gasoline mower has been lying idle for a while, and you have to get it started to trim your grass. I have seen a couple of people complaining about how their lawn mower won’t start after sitting all winter.
This can be very much frustrating, not to worry much though, in this post, I will be providing you with a couple of fixes that I have used to successfully getting my mower running. I will be focusing sorely on gasoline mower for this, chiefly because it is the most widely used. I will start by taking you through a typical simple process of starting your mower in stages.
How to start a lawn mower that has been sitting?
First of all, you have to make sure that your mower is positioned on a clear surface. You would not want to start it on a surface with pieces of metals, for example, because these can damage your blade and potentially injure you.
Pull the choke to the full mode or press prime bulb three times in some models. This will channel fuel to the engine; however, there is no need to do so if you have recently used the mower. For those who are not familiar with a choke or prime bulb here are a few things about them:
Both devices are an inbuilt device used to enrich the fuel mixture, which enables the smooth start of a cold engine. The engine runs best when the fuel-air ratio is 14.7:1. You also get full combustion with this mixture. A leaver controls a choke plate, and the use of a thermostat automates some. The choke reduces the quantity of air, increasing the fuel reaching the engine. The prime bulb creates fuel-rich conditions by squirting fuel into the engine.
Firmly hold the bail lever (deadman’s lever). A bail bar is located on top of your handling bars, keeping it is a safety precaution that prevents the blade from spinning and killing the engine within three seconds of activation of bail leaver.
Grab the pull cord and pull it quickly with considerable force till the engine runs. When you remove the chord, the engine has to run at 350rpm (revolutions per minute) for a spark plug to produce a spark to ignite the fuel-air mixture. Please do not give up after the first attempt of pulling, and it requires you to perform up to three attempts. If these do not work, stop for a few minutes and try again.
Soon as your engine starts running, you have to push throttle lever to full throttle or fast run if the mower is fitted with manual choke. This prevents your mower from producing black smoke if run under choke for too long, which ultimately shortens its life. I hope with this the “how to start a lawnmower ” question has been answered.
What to do when lawnmower doesn’t start after sitting through winter.
Possible trigger 1
Picture this, your mower won’t start after sitting all winter, yet you remember and confirm that you left a significant amount of fuel in the tank. So, how to start a lawn mower that has been sitting over the winter? The fuel certainly has to work no matter what, right? Wrong!. The thing is every fuel has a useful life. Petrol/gas has a shorter useful life, while diesel has a longer useful life. Thus the first culprit has to do with expired fuel, and this brings me to the first fix, which is to follow:
Fix 1: Replace the fuel
This requires you to drain out all of the old fuel from the tank using a siphon horse and replace it with new fuel. Now, as a future preventative measure, I advise you to use a fuel stabilizer. This will ensure your fuel stays fresh for up to two years; thus, you will not have to worry about having your mower idle. I recommend sta-bil gas treatment in which one ounce treats up to 2.5 gallons of fuel. It effectively cleans the fuel system and prevents gumming. Pull the mower’s chord and check if this has solved the problem.
Possible trigger 2
When lawn mowers won’t start even though you have replaced the old fuel? Do not worry. There is a good possibility that the fuel-air mixture reaching the cylinders is too lean. Thus you need to adjust the fuel-air mixture ratio going to these cylinders by executing the following fix:
Fix 2: Priming the engine and or use of choke
Push the prime bulb three times; you should see fuel in the glass window behind the bulb. If your mower has a choke, then turn it on. However, switch it off soon as the engine gets going or after several attempts and wait a few minutes before reattempting.
Possible trigger 3
A sluggish start with perhaps a sudden dying out of the engine can be a sign that there is a need for oiling to be done. You especially have to check the oil levels before starting your four-stroke mower, which has been sitting all winter. Oil lubricates all moving parts such as the pistons, and therefore in its absence, friction will be great, making it challenging to get the engine going.
Fix 3: Top up with oil.
In case the oil levels are down, especially after last season’s use, you need to replenish it. This will require you to mix your fuel with the oil in a ratio as stipulated in the user manual of that particular mower’s model for a two-stroke mower. Too much oil is just as bad for your engine as too little oil, so follow the manual’s instructions.
Possible trigger 4
If your mower has an electric starter with a battery for initiating the engine’s running, then possibly the battery may have drained while the mower was sitting unused.
Fix 4: Recharge/boost battery
Recharge the battery using DC, make sure positive and negative cable clippers of charger go respectively on the correct battery terminals to prevent battery damage. In some cases, this battery would have reached its useful life and will require agent replacement.
Possible trigger 5
Do you smell a build-up of fuel vapor as you go on trying to restart your mower?. If you do, it indicates that the carburetor or cylinders are flooded with fuel so that the fuel-air mixture is deficient of air. Here is a quick fix for that:
Fix 5: Leave your mower for about 15 minutes.
By leaving your mower on flat ground for some minutes, you will be allowing the fuel flooding carburetor to evaporate and leave the mechanism, thus solving the issue.
Possible trigger 6
When your petrol mower remains silent even though you have tried other fixes, the problem might have to do with the spark plug. This device is essential because it is the one that ignites the fuel. You can attempt the following fix:
Fix 6: Cleaning the spark plug
Soot from combustion accumulates between the plug’s gap, thus preventing the formation of essential sparks. You will need a spark plug wrench to remove the plug from your mower. After removing it, the soot’s brush and slightly use the emory board to get the shiny metal appearance between the gap. Replace the plug and try restarting the mower. Sometimes the plug might have been worn out so that it requires a replacement.
A final thought on fixing a lawn mower that has been sitting
As you have seen, starting a lawnmower is a reasonably straightforward process. May I recommend keeping your mower in a secured dry storeroom raped in plastic till next season. This will prevent air moisture from getting into the fuel tank and carburetor, where it will condense and trigger problems related to starting the engine.
In addition to this, make sure you drain out fuel from mower’s tank before keeping it idle for a while, I am sure you will have better use for that fuel than getting it wasted. It will also be wise for you to always carry out maintenance on your lawnmower during that sitting period. Hopefully these help a lot if your lawn mower won’t start after sitting all winter.
You can start by installing new spark plugs before the period you want to use the mower. Also, inspect for some hidden oil or fuel leakages by looking for any leakage spots. Otherwise, the failure of all the fixes provided would mean your engine is dead! Therefore you would need to get yourself a new mower.
Paul Culbertson says
Wash and dry your lawn mower after the mowing season is over. A power blower can be very helpful in removing grass and debris from the underside of your lawn mower and other hard to reach areas. If your lawn mower engine is air-cooled, use a stick or wooden dowel to remove any residue from the cooling fins.