Over the years, I have heard stories of inopportune times when lawn mowers wouldn’t start. Many times, mowers stopped working in the middle of a customer’s lawn or right before a big rain storm, or before a big party. As the owner of a lawn mower, you will most likely come upon a time when your Craftsman lawn mower doesn’t start and it may be at a time when you need it most.
A Craftsman lawn mower won’t start when the engine is not getting air, fuel or spark due to a plugged air filter, bad fuel, faulty switches, bad battery, bad spark plug, fuel blockages or dirty carburetor.
Keep reading for my complete list of items that can prevent your Craftsman lawn mower from starting.
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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, knowledge or are not in the condition to perform the repair safely.
Reasons Why Your Craftsman Mower Won’t Start
1. No Gas in Your Craftsman Fuel Tank
Having gas in the gas tank seems like the obvious answer, but it is often overlooked. I’m just mentioning it just in case you forgot to check.
Fix: Fill with fresh gasoline with an octane level or 87-grade or higher. Choose a gas with an ethanol level no greater than 10%. Find more information on the correct fuel for your gas lawn mower here.
2. Bad or Old Fuel in your Craftsman
Gas begins to breakdown and become less effective after about 30 days. This is why it is important to purchase your fuel from a busy gas station where fuel isn’t sitting around for long periods of time. Only purchase what you can consume within 30 days.
The ethanol included in gas today is an environmentally friendly substance that works fine in vehicles, but it is not a good choice for lawn mower small engines. Ethanol attracts moisture and when that moisture evaporates, gummy residue deposits can be left in the fuel system to clog fuel lines, filters and the carburetor.
To read more about the correct gas to use in your lawn mower and ways to extend the life of your fuel, read my article “This is the Type of Gas Lawn Mowers Use”.
Fix: Remove the old fuel, flush the tank and add fresh fuel. Adding a fuel system cleaner like Sea Foam is a good idea especially after running old gas through your Craftsman lawn mower.
3. Bad Craftsman Fuel Cap
Your gas cap has a vent. When this vent gets plugged, the fuel tank forms a vacuum preventing gas from moving through the fuel lines. Your Craftsman acts like it is starved of fuel when it is unable to pull gas due to improper venting of the cap.
Fix: Try to clean the cap to open up the vent. Replace if your cap is broken or you are unable to get your cap to vent.
4. Bad Spark Plug or Loose Connection in Your Craftsman
Another reason your Craftsman won’t start may be due to a bad spark plug connection or a damaged spark plug. An excessively dirty spark plug can foul out causing your engine to misfire.
Fix: Remove your spark plug and inspect it for signs of carbon buildup or cracked porcelain insulator. Replace with a new spark plug(s). Make sure to gap them according to manufacturer specification.
5. Craftsman Has a Plugged Air Filter
Your air filter should be cleaned or changed frequently so your engine can continue to pull in clean air. When air flow is blocked because of a plugged air filter, the engine runs hot and searches for air where ever it can find it including air remaining in the crankcase.
Fix: Clean your paper air filter by removing it from the air filter housing, being careful not to drop any dirt into the intake. Tap the filter against a solid surface to remove excess dirt. Hold the filter up to the light to check to see if light can be seen through every area of the filter. If you cannot see light, you must replace the air filter.
You can find information on other types of air filters here.
6. Bad Craftsman Fuel Pump
When your fuel tank is lower than the carburetor, you will have to pump fuel to the carburetor using a fuel pump. The fuel pump will have three ports: inlet port, outlet port, and port that is connected to a line off of the crankcase that pressurizes the pump.
You may be able to visually recognize your fuel pump is bad by checking the pump for small cracks or fuel leaking. You will have to replace the fuel pump if you see cracks or fuel leaking outside of the pump. If the fuel pump appears to be in good condition, you need to check the fuel lines to make sure fuel is getting to the fuel pump and fuel is being pumped out of the fuel pump.
- Verify you are getting fuel to the fuel pump. Turn off the fuel valve or use a clamp to stop the flow of fuel. (Not every mower has a fuel valve). Disconnect the line from the inlet port of the fuel pump and place in a container that sits lower than the fuel tank. Unclamp or turn on the fuel valve and check to make sure fuel is flowing out of the tube into the container.
If you are not getting fuel, check your fuel lines of fuel filter for blockage.
- Verify your fuel pump is pumping fuel to the carburetor. Reinstall the first fuel line you took off by connecting it to the fuel pump inlet. Remove the fuel line from the carburetor. Place tube in a container, start the lawn mower, and watch the end of the fuel line to make sure fuel is being pumped out of the fuel line into the container. You should have a steady flow or pulsating flow of fuel coming out of the fuel line.
Replace the fuel pump if it is unable to consistently pump fuel out of the outlet port.
7. Plugged Craftsman Fuel Filter
Your fuel filter strains the fuel coming out of your fuel tank and running through your fuel system to keep out any dirt or debris. Old fuel can leave gummy deposits, when it evaporates, that may plug the fuel filter.
Fix: A fuel filter that is cracked must be replaced. You can check whether fuel is being passed through the filter by removing the fuel line after the fuel filter and placing it in a container to see if you have fuel flow.
Use a clamp to stop fuel flow while you are moving the line into the container and then remove the clamp to test flow. Replace a fuel filter that doesn’t allow fuel to pass through.
8. Blockage in the Craftsman Fuel Line
Old fuel that gummed up can become lodged in your Craftsman mower’s fuel line.
Fix: Remove the fuel line. Next, you need to spray a carburetor cleaner into the tube and use compressed air to blow air through the tube until the line is no longer clogged. You can also replace with new fuel line.
9. Clogged & Dirty Craftsman Carburetor
The carburetor is an essential component to your Craftsman lawn mower. Its function is to make sure your engine receives the right mixture of gas and air to create a combustion in the engine. Without this correct ratio of gas and air, your lawn mower may run rough and may not be able to start.
Fix: Your carburetor can be replaced or clean. Most of the time, cleaning your carburetor will do the job and your Craftsman will be up and running again. You can find steps for cleaning your carburetor in this article.
10. Craftsman Has a Bad Battery, Loose Cables or Corroded Terminals
To continue to check for your Craftsman starting issue you will need to check the battery, cables and terminals. The battery must be charged at a reading of 12.7 volts or greater. Loose cables and corroded terminals can contribute to starting issues.
Fix: Clean corroded terminals in a baking soda solution containing 2 cups of water and 3 rounded tablespoons of baking soda. Use a wire brush to scrub the terminals clean.
Test your battery with a multimeter. If you receive a reading of less than 12.7 volts, you must charge your battery. Read more about the steps and items needed to charge your battery here. If your battery does not hold a charge, you will need to replace it with a new battery.
You can purchase lawn and garden batteries at hardware and auto parts stores. Many stores that sell batteries will charge you a core fee if you don’t have the bad battery to give them. Don’t forget to bring your battery with you.
11. Bad Safety Switch in Your Craftsman
A Craftsman mower uses several safety switches in order to keep you safe when you are operating the lawn mower. These switches can become faulty and cause your lawn mower to not start.
Fix: Test the switch using a multimeter or you can temporarily bypass the safety switch to identify a bad switch. Do not operate a mower without the safety switch installed for your safety. Always have safety switches installed and working on your equipment.
12. Craftsman Has a Bad Ignition Switch
You insert the key into your ignition switch and turn it only to find your Craftsman doesn’t start or even turn over. The ignition switch could be the problem.
Fix: You can use a multimeter to test the ignition switch. Replace the switch if bad.
13. Bad Recoil on a Craftsman Push Mower
Many Craftsman push mowers are pull-started using a recoil. When that recoil is damaged or the parts fail, the mower is no longer able to be started using the recoil. A bad pulley, broken spring or broken clips are likely to be the culprit of a broken recoil.
Fix: You can attempt to replace the spring and restring the recoil. If it does not work because other components in your recoil are damaged such as the clips or pulley, you are better off just replacing the recoil assembly.
14. Bad Craftsman Ignition Coil
The ignition coil provides voltage to the spark plug so it can fire and start the engine. The engine will not start if the spark plug isn’t able to fire.
Fix: After you verified your spark plug is in good condition, check the continuity of your ignition coil using an multimeter. Replace the ignition coil if you find a break in the continuity.
15. Bad Starter Solenoid on Your Craftsman Mower
A lawn mower solenoid is an electromagnetic switch that is like an on-off switch that actuates the starter motor to turn over the engine. A click or hum when turning your ignition key is an indication to check your solenoid. Another indication your riding mower solenoid may be bad is when a wire attached to your solenoid gets hot and begins to smoke or melt.
Fix: Test your Craftsman mower solenoid by following the steps here. Replace your solenoid if it is found to be bad.
16. Faulty Charging System on Your Craftsman Mower
The charging system can drain the battery and cause your Craftsman mower to not start. A bad stator or alternator can be the problem. I show steps on how to test your charging system here using an ohm meter.
Fix: If you find the problem is in your charging system, have a small engine mechanic identify what is the actual cause of the failure. It could be several different items and you will just be guessing at the problem which gets pretty expensive.
17. Incorrect Operating Procedure to Start Your Craftsman Mower
There are specific instructions for starting different types of Craftsman mowers. A reason these specific procedures are put in place is for safety reasons. For example, push mowers use a safety bar to recognize the operator. Riding mowers use a seat switch to confirm the operator is still on the mower. They also use a brake switch that can fail to allow the mower to start if the brake is not engaged.
Fix: Refer to your Craftsman operating manual to ensure you are operating your lawn mower correctly, so you don’t set off the safety features that shut off your lawn mower.
Craftsman Lawn Mower Stops Running
Many items that prevent a lawn mower from starting are also reasons why your Craftsman may die when cutting your lawn. There are additional items to check if you are experiencing this problem. Read my article “Why Your Craftsman Dies & How to Fix“.
Craftsman Lawn Mower is Smoking
Another problem you can encounter with your Craftsman is the problem of your mower smoking. Smoking occurs when other substances burning in your fuel system or the engine gets hot and begins to burn oil. Find more information in “Why Your Craftsman is Smoking“.
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 you 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.