If you have ever gone out to mow the lawn and suddenly realized that your lawn mower won’t start, then you know the pain of this situation all too well. Whether it is due to a dirty carburetor, you have a malfunctioning spark plug, not enough gas to the engine, or simply a clogged air filter, there are many reasons why this could be happening.
When your lawn mower has this problem, you essentially have one of two choices. Either take your lawn mower into a service shop or try to fix it yourself.
Since the most common cause of why your lawn mower starts then dies is due to a carburetor problem, you can typically fix it yourself. The first step is to analyze the problem, and then you can follow the steps below to fix it.
Understanding Your Carburetor
In order to fix your lawn mower, you will first need to understand how your carburetor works. Concerning other motors, if you own a motorcycle or any other small gas-powered engine, then you have a carburetor. The main function of the carburetor is to mix the gas and air. It does this to make it more combustible, and allow the pistons to burn.
Carburetors mix exactly the right amount of oxygen and gas. This is called AFR (Air Fuel Ratio). After starting your engine, gas will flow from the tank and will go into the carburetor bowl. Inside the bowl, there is a floater and this controls gas going in and out of the bowl.
As you start the engine, the air is sucked through the vent. Then, air pressure atomizes the gas and mixes this with the oxygen. This mixture will spray into an even finer form, and go into the spark plug chamber. It now creates a spark and the engine will run.
Essentially, if your lawn mower starts then dies, you should first look into the carburetor. You can also look into the items that are also attached to it. Here we identify the common problems the carburetor has and also the best solution to fix these.
Reasons Your Lawn Mower Starts, then Dies
If You Have a Loose Carburetor
If you have a loose carburetor, then your engine will not function properly. This is because you will not have a full flow of gas, nor will the atomization of gas be stable.
To avoid this, check to make sure the carburetor is firmly attached. This can help you to know if you have serious problems, or if you simply need to tighten your carburetor.
Is Your Carburetor Clean?
This is incredibly important if you want to see if your carburetor is working. Make sure to clean it with a carburetor cleaner, and get off all the dirt and grime that has built up. This is a very easy fix and might allow your mower to start.
Clogged Carburetor Bowl
Since most carburetors today have their carburetor bowl underneath, attached by a screw with a hole at the bottom, it is very easy for this hole to get clogged. When this happens, air won’t be able to pass into the carburetor. This prevents the downward movement of gas and will cause your lawn mower to stall.
To fix this, remove the bowl screw. You can do this by using a ½ inch plug wrench. Be sure to clean the dirt out of the bowl, and then out of the screw as well. If you cannot wash it easily, take a very small wire and thread it to remove any dirt.
Once again take your carburetor cleaner and spray the hole. As you go to recap the bowl, try not to overtighten the screw as this can affect the seal.
Residues from Old Gas
When you leave gas out for a long period of time, often it can form a residue. These residues can clog the parts of your carburetor internally, and then restrict the gas inside. To remove these residues you should drain out the old gas, and replace it with fresh fuel.
Be sure to add a fuel stabilizer as well as this will enhance the quality of your fuel and prevent future residues to form. Using a fuel stabilizer can make your gas usable for up to two years.
Dirty or Defective Spark Plug
If you have a dirty or non-working spark plug it might be due to a huge amount of carbon build-up. This typically happens in the socket of the spark plug, and will eventually weaken it.
Always make sure your spark plug is not worn out. Check the spark cap for dirt as well. If you do see signs of carbon deposits or oil be sure to clean it up. Unfortunately, sometimes the only answer is to replace it.
Gasoline Cap is Blocked
Although not all do, some gasoline caps have holes in them. This can help to stabilize air pressure inside your gas tank. If you do happen to have these holes on your machine, if the holes get blocked you will have a major issue.
Basically, the blocked hole creates a vacuum in your tank. This will once again disrupt the gas flowing into the carburetor. The fix for this is simple, clean the hole with a small wire. If the cap is damaged you should purchase a new one.
Too Much Oil
Although you would never assume this would be a problem, if you have too much oil in your machine then you may have too much oil in your oil reservoir. Always be sure to clean your carburetor first.
If you have cleaned your carburetor, your engine stalls, and there is also white smoke coming out of the engine, then that is a sign of too much oil.
If you have been using your Briggs and Stratton lawn mower for many years, then your carburetor might eventually fail you. Whether you simply need to repair it, or you need to replace it, these are great lawn mowers and are worth fixing.
How do I know if I have too much oil in my reservoir?
Tilt your lawn mower up and put a heavy object on the handle. This should hold it up. Allow the oil to go to other parts of the engine, leave it for about an hour. Then run the machine and see if it runs for a while without dying. If this happens, then you simply have too much oil.
How long should I go without cleaning my carburetor?
Cleaning your carburetor every six months is a good idea. If you are a commercial business and use it more often then you may want to do so even more often. Maintenance is key to keeping healthy machines.
How often should I change my oil?
You should change your oil either every 25 hours of use or every season.