My Lawn Mower Is Hard To Start

Lawn mowers can be finicky machines. They can be easy to start one day and hard to start the next. In most cases it is a simple adjustment to make them easier to start.

This adjustment is often a valve adjustment. Over time the valve clearance become loose and will not allow the valves to open properly. If the intake valve does not open fully, a fresh charge of gasoline will not make it into the combustion chamber. If the exhaust valve does not open fully, the hot gasses will not be expelled out the exhaust pipe and it prevents fresh gas from coming into the combustion chamber as well.

An engine is basically an air pump. Air goes in and air goes out. Whenever that cycle is interrupted, it makes it hard to start the engine. Try adjusting those valves to their proper specification and see if it makes a big difference in the starting of that engine.

You should also check to make sure that the choke is working properly. An engine choke is a butterfly type valve and you close in the carburetor. When it is closed, it creates more vacuum inside the carburetor and pulls more fuel through it and into the engine. If the choke is not closing fully, then fuel will not be adequate enough for a cold start operation.

By adjusting the choke and valves, you should have an easier starting lawn mower.

My Lawn Mower Won’t Start

Are you getting ready to cut your grass in the spring or is this something that happened during the mowing season?

If it is springtime, then more than likely the gasoline in the engine is causing it to not start. A thorough carburetor cleaning normally does the trick. In severe cases, replacing the carburetor is necessary because it just cannot be cleaned well enough. This would be the case of a lawn mower that has sat for several seasons.

On the other hand if you were mowing last week and you tried to start your lawn mower today and it didn’t start, there could be an assortment of reasons why it won’t. You could be out of gas. There may be no spark. Your flywheel key could be sheared. Something could be plugging up the fuel line. The spark plug could be bad. Your air filter could be clogged. Mice could have chewed up the ignition wiring and a bunch of other things could be happening.

With this scenario, you need to have a small engine mechanic check it out and troubleshoot the problem. You can find a lawn mower repair shop in your area by visiting our Locations page.

Push Lawn Mower Won’t Start

An engine that won’t start won’t get much grass cut today. Your push mower has a single cylinder engine that is pretty basic. There are not a lot of fancy electronic controls for the electrical or governor systems and it is just a plain gasoline engine.

Every gasoline engine needs these things to run. It requires fuel, compression, air and spark and to troubleshoot why your engine will not start will require a systematic approach to figuring out why it won’t start.


Today, we always start out with the fuel you are using. Is it good and clean fuel? Does it have water in it? Is it older than 90 days? Good clean fuel makes all the difference in the world when it comes to starting your engine. As fuel ages, it becomes less volatile and harder to ignite as the vapors evaporate that ignite easily.


Without a compression gauge, it is hard to tell exactly how much compression your engine has. You can however get an idea of the compression that the engine has by how hard it is to pull the engine over with the pull rope. If there is a good bit of resistance, then you should have good compression.


A dirty air filter will cause your engine to run rich or get too much gas. You need the right mix of fuel to air for the engine to start properly. Check that air filter and if there is any doubt, replace it.


Obtain a spark tester and attach it to the spark plug and spark plug boot. Pull the starter rope and observe the spark. You should see a bright blue or orange color depending on what spark tester you have. If you have good spark, remove the spark plug and check its condition. Also check to see if it is wet with fuel. If it is, replace the spark plug and try to start the engine again.

If you are still struggling to get your lawn mower started, visit our Locations page for a small engine shop near you.



Troy-Bilt Self Propelled Lawn Mower Takes Many Pulls to Start

Are you pulling and pulling and then FINALLY your lawn mower decides it wants to start?

This is a pretty common problem with a Troy-Bilt lawn mower with a Briggs and Stratton Overhead valve engine. After a while the valve lash will become tight and not allow the valves to open far enough to let fuel in and exhaust out. If not enough fuel comes into the combustion chamber, then it will not ignite and burn properly.

If you are mechanical by nature, remove the valve cover and set the engine at Top Dead Center and check the valve clearance. One these small engines, the intake is set at .004 and the exhaust at .006 to have them run at their best performance.

Adjust the valves if they are not in specifications and reinstall the valve cover with some Triple Bond sealant. Let it dry for a few hours before you test run the engine to see if you have solved the problem.

If after your repair it still is hard to start, check the fuel and choke system to be sure that they are working as they should.

If you need a Troy-Bilt small engine mechanic to help with your lawn mower, visit our Locationspage to find a shop near you.

How to Start a Hard Starting Lawn Mower

You are struggling to start your lawn mower and you just feel like pushing it over the nearest hill…well that is, if you have a hill!

Lawn mowers can be a real pain if everything is not working properly and a hard starting one can be frustrating. So, let’s see if we can take some of that frustration out of it for you.

A hard starting lawn mower can either have a fuel issue, ignition or a mechanical one.


You can check if the lawn mower is getting fuel by trying to start the engine and then removing the spark plug after you stop cranking. See if there is any gas on the plug. If not, it could be a fuel delivery problem such as a plugged up carburetor or fuel filter.


You can also install a spark tester at this time to see if you have good spark.


A choke that will not fully close is another issue that causes hard starting. Engage the choke fully and make sure that is closes completely.

Improperly adjusted valves is another item that will cause hard starting. Check the valve clearances to ensure they are in specifications.

Low engine compression can also cause this problem.  Check for the proper PSI that your engine should have.

These are some simple things that you can check and see if you can resolve your lawn mower problem. Perform these steps and hopefully you will find the problem!


My Lawn Mower is Hard To Start

A hard starting lawn mower can be a real pain to get started and it can be even harder to start after you shut it down for a minute or so to pick something up from the yard.

Hard starting is generally a carburetor choke problem or a valve issue. But there are other things that can cause it and they will be covered here as well.

Choke springs or incorrect setup of the choke can make your engine very hard to start. It will not be resolved until the choke is repaired properly and tested when the engine is cold and hot.

A valve issue is a little more complicated. A valve could have a lot of carbon buildup on the valve stem causing it to stick open or closed. Or the valves could be out of adjustment. A good lawn mower mechanic can adjust the valves and get your engine starting much better and easier. A pull start lawn mower should start within 2 pulls of the starter cord. A riding lawn mower should start within a few revolutions of the engine. Another thing that can cause hard starting is a valve seat that is coming loose and not sealing well. The seat will have to be replaced to correct this issue.

One more possible scenario is that your air filter could be so clogged that the engine is not getting enough air to start. Check the air filter to see what condition it is in and replace it if it is suspect.

Your engine could also have a leaking head gasket. A compression and leakdown test will need to be performed to see if that is the issue here.

Lastly, you could have water in your fuel or the wrong fuel in the fuel tank. It is not uncommon to see diesel fuel filled gasoline tanks, so if the fuel is in doubt, drain the tank and carburetor and refill with fresh fuel.  Check our locations page for a shop nearest you.

I hope these tips will help you get your my lawn mower is hard to start back up and running once again.

My Lawn Mower is Hard to Start

This is a very common problem. You keep pulling the pull cord until it finally starts or you turn the key and crank and crank until it finally starts. Both result in the same hard starting lawn mower engine.

It comes down to a common few things that cause this problem. One is you are not getting enough fuel in the engine because the fuel pump is going out or there is an obstruction in the line, fuel filter or the carburetor.  Try turning the engine over on a riding lawn mower with the fuel line disconnected at the fuel pump outlet line and have a catch can waiting to catch any fuel that comes out. If fuel comes out readily, then your fuel pump is fine.

On a gravity fed system. unhook the fuel line at the carburetor and see if fuel comes out. You will need a tool to pinch the fuel line closed and they make a special one with smooth jaws for this. If you don’t have a way to stop the fuel from flowing, you will have a big mess to clean up!

If fuel is going to the carburetor, then pull the spark plugs and make sure they looks slightly wet with fuel. If they are, the problem is most likely your valves are out of adjustment.

On a push or self-propelled lawn mower, to test for fuel getting to the engine, pull the cord or turn the key on an electric start a few times and then remove the spark plug and see if there is fuel on it. If there is, your valves are probably out of adjustment if it is an overhead valve engine.

Another common item to cause this problem is the choke not set properly or it is malfunctioning. Check to be sure it is closed when you are starting the engine and slowly opening as the engine warms up.

Blown headgaskets can also cause hard starting and low cylinder pressures due to bad piston rings or valves that are not seating well. The carburetor may not be venting either and throwing a lot of fuel into the engine flooding it. The needle and seat may be failing an flooding the engine as well.

Bad fuel or water in the fuel can also cause hard starting in your lawn mower.

Check each system one at a time to help narrow down what the problem is and then find out which specific component is the culprit to solve my lawn mower is hard to start problem.