Why Your Craftsman Lawn Mower Start Then Dies (How to Fix)
It’s frustrating when you finally get time to mow and find yourself stuck in the middle of your lawn with a dead lawn mower. You need to get your lawn mower started again, but where do you really begin to check over your mower for the problem?
If I were you, I would start checking for fuel and air restrictions. Lawn mower engines need air, gas, and compression. When your lawn mower lacks one of these items it will stop running.
Keep reading as I have compiled a list of items that can cause your Craftsman lawn mower to die while mowing.
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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing, or operating.Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
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Reasons Your Craftsman Lawn Mower Starts Then Dies
Your Craftsman Lawn Mower may start and then die when your lawn mower is unable to regulate the air-to-fuel mixture required by the engine to form a combustion. This could be due to a dirty carburetor, bad fuel, plugged air filter, broken fuel pump, plugged fan, or other components that can restrict fuel or airflow.
Fuel Problem in Your Craftsman Mower
I am assuming the first thing you checked when your Craftsman mower died was the fuel tank to check the gas level. Even though your lawn mower has plenty of fuel in the tank, fuel can still be a problem.
One of the most likely causes of your lawn mower dies is due to fuel issues.
Here are fuel related items to check:
Bad Fuel in Your Craftsman Mower
Did you know that gas is only good for 30 days before it begins to break down and become ineffective? In much of the fuel used today, a corn-based product called ethanol is added to make fuels more environmentally friendly.
While ethanol-based fuels are fine to run in your vehicle, it is not good for small engines like the engine in your Craftsman.
Ethanol not only attracts moisture but also will separate from gas over time and become very damaging to your engine. Ethanol is corrosive to your fuel system dissolving plastics and leaving behind deposits.
These deposits in your fuel system create buildup and blockages which cause damage to your lawn mower.
To protect your lawn mower and not prematurely shorten its life span, always use your fuel supply within 30 days.
Not only does fuel begin to break down, but ethanol that attracts moisture in your system will eventually separate and the ethanol and water will sit at the bottom of your fuel tank. This separation is not easily seen when looking into your fuel tank.
You can add a fuel additive to your gas as a preventative measure to prevent moisture buildup and fuel separation. In fact, I highly recommend adding Sea Foam Motor Treatment to your fresh fuel. You can read more about it in “Why Use Sea Foam Fuel Additive in a Lawn Mower”.
FIX: Drain the fuel tank by removing fuel and placing it in a container for recycling. Flush the fuel tank and fill it with fresh fuel treated with Sea Foam. Not only does Sea Foam stabilize your fuel, but it can also be used as a fuel system cleaner.
Wrong Fuel in Your Craftsman
With so many different fuels on the market today, it is very easy to grab the wrong kind of fuel at the gas station. Sometimes it may be a little difficult to differentiate the fuel differences. You can’t always go by the color of the handle as they can vary between fuel stations.
Small engines require unleaded gasoline with an octane rating of 87 or greater. The gas must also contain no greater than 10% ethanol. Read the sticker on the fuel pump that shows both the octane rating and ethanol content percentage.
Most gas stations will carry fuels with 10% (E10) and 15% (E15) ethanol contents. Avoid using the E15 fuels and especially the E85 fuel that is beginning to appear at more gas stations. For a more in-depth look at fuel for your Craftsman lawn mower, check out my article here.
FIX: Drain the fuel tank, flush the fuel tank and fill it with fresh fuel treated with Sea Foam Motor Treatment.
Dirty Carburetor on Your Craftsman Mower
A dirty carburetor can be the reason your Craftsman mower starts and then dies. The deposits left behind by bad fuel can create a buildup in your carburetor.
When the carburetor is dirty it may not be able to properly regulate the air and gas mixture required to create a combustion.
FIX: Most of the time the carburetor can be cleaned, but other times the buildup of deposits can be so bad that it is unable to be efficiently cleaned. You may not even want to tackle cleaning your carburetor and find it easier to just purchase a new one and replace it.
If you are mechanically inclined you can try to clean your carburetor yourself, otherwise, a lawn mower repair shop will be able to help you.
Read my steps on how to clean your lawn mower carburetor here.
Craftsman Has a Broken Fuel Pump or Plugged Fuel Filter
The fuel pump is needed on a lawn mower where the fuel tank sits lower than the carburetor. The pump exists to assist in pumping fuel to the carburetor. Check your fuel pump for failures along the seam that may leak fuel.
Internal damage will be harder to spot visually, so you will need to perform some tests to ensure it is receiving fuel and pumping fuel.
FIX: If your lawn mower has a fuel shut-off valve, you will use this to start and stop fuel flow while testing your fuel pump.
If you don’t have a shut-off valve, you can use clamps to clamp the fuel lines to start and stop the flow. You will fill check for flow to the fuel pump by checking to make sure fuel is flowing through the fuel line flowing to the fuel pump.
If fuel does not flow to the pump, you will need to check for obstructions in the fuel lines or the fuel filter. Once you have fuel in the pump, you will check to ensure fuel is being pumped by the fuel pump.
To do this, remove the fuel line from your carburetor and place it in a container. Start your mower and watch the end of the fuel line. If your fuel pump is functioning correctly, you should see a steady or pulsating stream of fuel being pumped into the container.
Replace your fuel pump if you don’t see your fuel pump isn’t working properly.
Blocked Fuel Lines
You may have blocked fuel lines. If you notice fuel isn’t getting fuel to the fuel pump or from the fuel pump to the carburetor, you may have a blocked fuel line on your Craftsman.
Use the method above the fuel pump section to identify whether fuel is being carried through the lines without restriction.
FIX: To clear the line, remove the fuel line and blow air through the line using a can of compressed air. Reinstall the line. The fuel line can easily be replaced with a new fuel line which can be purchased on Amazon or your local hardware store.
Bad Gas Cap
Something as simple as a gas cap can cause your Craftsman mower to die. Fuel caps on are designed to vent. When the vent is blocked, a vacuum is created in the fuel tank which restricts the amount of fuel flowing through the fuel tank.
FIX: Remove your fuel cap and start your lawn mower, allow it to run. If your Craftsman no longer dies, this can be your problem. Be careful to not let any dirt or debris enter your fuel system when testing your mower without the fuel cap.
You can try to see if you can clean the cap to allow it to vent. If you cannot, you need to replace the gas cap.
Air Circulation Problem in Your Craftsman Mower
Plugged Lawn Mower Air Filter
The engine requires air that is filtered through the air filter in order to run. If the air filter is plugged with dirt, grass, and other debris, the mower is no longer able to get the air it needs.
This will cause your Craftsman lawn mower to run terribly and die because it is being starved of air.
A clean air filter should be used in your lawn mower. A plugged filter doesn’t only cause your engine to shut down, but it can result in your engine overheating causing internal engine damage.
FIX: Remove the air filter. If your air filter is a paper filter, knock the dirt out of the filter by tapping the filter against a solid surface. Hold the air filter up to a light and make sure you see light through the filter.
You will need to replace the air filter if you are unable to see light through the paper filter.
Your Craftsman lawn mower may use a different style of the air filter. For cleaning procedures for other types of filters, read this article.
Dirty or Damaged Cooling Fins
Cooling fins can get packed with dirt, grass, and oil. When the fins are broken or packed with debris, the fins are not able to effectively circulate air around the engine block and cylinder head to keep your engine cool.
FIX: Remove the engine cover and clean the cooling fins. Replace any damaged fins.
Other Problems that Can Cause Your Craftsman Mower to Die
Too Much Oil or Too Little Oil in Your Lawn Mower
Too much oil in your Craftsman lawn mower can cause your engine to smoke and die while mowing. The smoke can clog your air filter causing your engine to look elsewhere for air.
Too much oil in your lawn mower can cause significant damage including internal engine damage and the possibility of having to replace your engine.
Too little oil in your Craftsman mower will cause additional friction in the engine that can cause your engine to overheat and die.
FIX: Perform your engine oil change according to Craftsman’s recommendations. Always fill oil to the correct oil fill levels.
Plugged Mower Deck & Dull Blades
A Craftsman mower deck that is packed with grass and dirt or a deck that is running dull blades can cause your engine to have to work harder. Your blades may be hitting debris each time it turns putting a draw on your engine. This can make it overheat and shut down.
FIX: Inspect your mower deck for any damage. Scrape the deck to remove debris and sharpen the blades. Always run your mower at full throttle when cutting grass. Avoid cutting wet grass.
Perform Routine Maintenance on Your Craftsman
Many fuels, air, and electrical issues with your craftsman lawn mower can be caught before they become significant problems when conducting regular maintenance on your Craftsman lawn mower.
I share more about operating your Craftsman riding mower along with maintenance schedules in “A Guide to the Craftsman Riding Lawn Mower”.
Still Having Problems With Your Craftsman Lawn Mower?
It would be nice to own a mower that will never give you problems. However, they don’t exist. Own a lawn mower long enough that you are bound to run into problems.
The most common of them are problems with starting, smoking, dying, vibrating, and cutting.
I put together a handy guide to help you quickly identify items that can cause a problem in your Craftsman along with ways to solve them. You can find this guide at Common Craftsman Lawn Mower Problems & Solutions.
If you are unsure how to safely perform diagnostics and repairs on your Craftsman lawn mower, it’s best to have a professional complete the repairs.
This will help you avoid personal injury or additional damage to the mower. Your local Craftsman lawn mower dealership or lawn mower repair shop will be able to help you solve your problem.
