Craftsman Mower Won’t Work: How to Fix It

Craftsman is a brand that has stood the test of time. An authentic American icon in tools and outdoor equipment, the Craftsman brand has become synonymous with quality after serving consumers for nearly a century. Consistent with their reputation, Craftsman lawn mowers remain some of the highest-rated and most popular mowers in the world.

Fixing a Craftsman lawn mower that won’t work involves identifying the problem, troubleshooting the source, and performing the proper action to correct the problem. The process can be as simple as making a minor adjustment or as complicated as replacing a transmission or another major part.

This article will discuss 12 common problems that can prevent your Craftsman lawn mower from working properly. From a mower that won’t start, to one whose engine can’t receive the gas, we will provide you with useful tips and tricks from established experts.

Lawn Mower Won’t Start

Diagnosing and fixing a Craftsman lawn mower that won’t start is one of the most complicated problems to solve. For example, there are more than a dozen reasons a lawn mower will not start.

For that reason, you will want to start troubleshooting the simplest problems to eliminate them before moving on to more complicated problems and involved solutions.

For instance, if you are using an electric mower, check to see if it is fully charged. If not, then plug it in and try starting it after it has fully charged. If you have a gas-operated lawn mower, check to see if there is fuel in the tank. If not, fill it up, fully engage the choke, and try starting it again.

The most common issues preventing a mower from starting include a dirty or clogged air filter, water in the fuel, and a faulty spark plug.

Let’s get started discussing those three issues.

Dirty Air Filter

A dirty air filter is one of the three most likely reasons for a mower not starting. Air must be filtered before it mixes with fuel in your mower and burns in its cylinders.

Grass and dirt fly up in the air around your mower every time you use it and can clog an air filter in no time. For that reason, you should clean your mower’s pre-cleaner for every 25 hours of use. Likewise, you should clean or replace your mower’s paper filter after about 300 hours of use or once a year.

Symptoms of a clogged air filter include a loss of power in your mower, increased fuel consumption, and trouble starting the mower. If your mower surges, stalls, or sputters when you attempt to start it, you probably have a problem with your mower’s air filter.

How to Clean an Air Filter

A lawn mower’s air filter is almost always located close to the top of your mower’s engine. Look for a plastic or metal shroud that is secured with snap fittings or screws. Then, you need to perform the following steps to clean your mower’s air filter.

  1. Turn off your mower and wait for all of its moving parts to come to a halt.
  2. Disconnect your mower’s spark plug wire.
  3. Remove the air filter case’s cover using a pair of pliers or a screwdriver. (An IRWIN Tools 9-in-1 Multi-Tool Screwdriver is perfect for this task as it includes both Phillips and flat-head tips. Likewise, a Craftsman Set of Mini Pliers is good for releasing snap fittings.)
  4. Rinse the foam pre-cleaner using gas, diesel fuel, gasoline, or water.
  5. Remove and replace your mower’s paper filter.
  6. Replace your mower’s air filter cover and fasten it.
  7. Reconnect your spark plug cable.

Important: don’t ever operate your Craftsman lawn mower without its foam pre-cleaner and air filter, or your mower can sustain serious damage.

How to Replace an Air Filter

  1. Turn off your mower and wait for all of it moving parts to quit moving.
  2. Disconnect your mower’s spark plug cable.
  3. Remove the cover for your air filter case using pliers or a screwdriver.
  4. Inspect your mower’s pre-cleaning filter. If it is brittle, stiff, or has significant yellow or brown stains, replace it.
  5. Remove the air filter, gently tap it to release any loose dirt and debris, and hold it up next to a lamp or bright flashlight. If the paper filter blocks a significant amount of light, it is time to replace it. If you have a foam filter, look for yellow or brown stains. If you detect any, it is best to replace the filter.
  6. Clean out the mower’s air filter housing using a dry cloth, taking care not to use any solvents since they can damage your air filter. Likewise, do not use a can of compressed air since it can force dirt and debris into your mower’s carburetor.
  7. Insert the new pre-cleaning filter and air filter into its housing and secure its cover using a pair of pliers or a screwdriver.
  8. Reattach your mower’s spark plug cable, and you are finished replacing its air filter.

Water in the Fuel

The presence of water in your fuel tank is another common reason your lawn mower won’t start. Your mower’s fuel gets contaminated by fuel typically by leaving it outside in the rain or snow, or condensation can occur if your mower is stored in a cold or damp environment.

There are three ways to detect if your mower’s fuel supply has been contaminated.

  1. Look for decreased performance. You might not be able to start your mower, or it might run normally and suddenly begin stuttering or might stall out completely. Additionally, you might see an unusually large amount of smoke coming out of your engine’s exhaust.
  2. Disconnect the fuel line and let a little bit of fuel drip onto a piece of metal or wood. If it beads up, that means there is water in the tank.
  3. Check your mower’s fuel tank using a flashlight. Gasoline is lighter than water, and if there is any water in the tank, it will sink to the bottom. Move your mower indoors into the shade, remove the fuel cap, and shine our flashlight into the tank. If you detect bubbles or globules in the gasoline, it is contaminated.

A basic Everready LED Flashlight is inexpensive and works great for checking our mower’s fuel tank for the presence of water. It is also great to have a flashlight handy in the event of any sudden power outage or other emergencies.

Draining Contaminated Fuel

You will need to drain your lawn mower’s fuel tank once your troubleshooting efforts detect the presence of water.

Perform the following steps to drain the contaminated fuel from our mower’s gas tank.

  1. Turn off the mower’s engine and wait for all moving parts to halt.
  2. Remove the mower’s spark plug cable.
  3. Pinch the fuel line using a pair of vice grips or a similar device and disconnect the mower’s fuel line. (Craftsman Fast Release Locking Pliers are perfect for performing this task.)
  4. Drain your mower’s gasoline into a container approved for gasoline and take it to your local auto parts store or disposal site for recycling. (The Garage Boss Press ‘N Pour One-Gallon Gas Can works perfectly for transporting contaminated gas.)
  5. Blow compressed air through the fuel tank and gas line to dry it out or let the mower sit overnight. (A can of Blow Off Duster works great for this task. )
  6. Reconnect the fuel line and fill your mower’s tank up with gas.
  7. Replace the spark plug cable and you are done.

Faulty Spark Plug

A faulty spark plug is another common reason that your mower won’t start since it provides the ignition source for your lawn mower’s engine. It is a fairly basic device with porcelain sheath that encases a center electrode, and a firing electrode that arches over the one at the center of the plug. It also has a threaded shank used to attach the spark plug to the engine block.

Symptoms that your spark plug is bad include difficulty starting your mower, or an inability to start it at all. Poor performance to include frequent stalling is also a symptom you should replace the spark plug.

Additionally, increased fuel consumption is another symptom your spark plug is bad. When your mower’s spark plug doesn’t perform properly, its gasoline doesn’t burn completely, and that results in increased gasoline use to compensate for the decreased ignition.

Replacing a Spark Plug

  1. Turn off the lawnmower and wait for all its moving parts to halt.
  2. Remove the spark plug cable.
  3. Remove the spark plug using a Briggs and Stratton Spark Plug Wrench or another similar tool.
  4. Inspect the plug for any signs of damage or wear. If its porcelain insulator is damaged or cracked, you need to replace the plug. Similarly, if the electrode is damaged or burned away or if it has heavy carbon buildup, you need to install a new spark plug. Additionally, you can use a Performance Tool W86554 Inline Ignition Spark Tester to determine if you need to replace the plug.
  5. Replace the spark plug and reattach the cable, and you are finished.

Belts Keep Breaking

Although Craftsman mowers are some of the best ones on the market, they can have problems with belts that keep breaking. If you have to replace your mower belt once a year or sooner, you have a problem with your mower that you need to resolve before it gets any worse. Remember, if you replace the same belt multiple times a year, you are probably treating the symptom of a problem and not the cause. That means that it’s time to figure out the root issue.

Bad pulleys are the biggest culprit when it comes to belt-related issues. Take the time to periodically check your belts for any excessive or uneven wear and tear. If you notice any, you probably need to replace the pulleys or the bearings. Additionally, you can inspect the pulleys and bearings themselves for any wear. When in doubt about them, it is best to go ahead and install new ones just to be sure.

Another cause for broken or thrown belts is a missing or damaged pulley guard. Yes, it can be a pain installing a new belt with the guard in the way. However, it also serves as a buffer to keep the belt on the pulley, so it needs to be there.

Accumulation of grass clippings on your lawn mower’s deck is another reason your mower may be braking or throwing belts. If enough grass builds up, some of it will inevitably work its way under the deck cover and over the pulley, which can damage or throw belts.

For that reason, you should take the time to brush off the deck when performing large mowing jobs periodically. Likewise, you should clean the deck after every use following the directions in your owner’s manual for your particular mower model.

Mower Won’t Drive or Self-Propel

Self-propelled and riding lawn mowers are great for minimizing the backbreaking effort required to perform large mowing jobs. However, once they quit working, it can be a pain to repair them.

However, if you know anything about working on automobiles, you are in luck since they share many of the same components. Likewise, they quit self-propelling and driving for similar reasons.

If your Craftsman lawn mower won’t drive or self propel, you need to check your battery, belt, carburetor, drive cable, filters, and transmission.

Battery Problems

A failing battery is a common reason your mower won’t drive or self-propel in any direction. Although a weak battery has enough power to start your engine, it may not have enough juice to drive or propel it. As a result, you might be able to start your mower. However, as soon as you engage the gears for movement, the power demand will increase, and your mower will likely stall.

Belt Issues

Your lawnmower’s drive belt is frequently the problem when using a self-propelled or riding mower. Power from the mower’s engine is transferred to its transmission using the drive belt. Over time, the belt can become stretched or damaged and can lead to an inability for the mower to drive or self-propel.

Typically, there is a belt tensioner built into the mower that can be adjusted to offset any stretching. However, if the belt is damaged, you need to replace it.

Additionally, over time the drive belt will wear down and become too thin. When that happens, it will start slipping on the pulleys, and it needs to be replaced at that point.

Carburetor Problems

Carburetors are another culprit when it comes to mowers that won’t self-propel or drive. The gasoline to air mixture can become too rich or too lean if your mower’s carburetor is damaged, and although it might start, it will stall out when you attempt to drive or propel it forward or backward.

Drive Cable Failures

Your lawn mower’s drive bail and transmission are connected using a drive cable. This cable engages your mower’s self-propel mechanism and varies the speed of your mower in some instances.

The drive cable will loosen over time. When that happens, you will need to tighten the adjuster which is located at one end of the drive cable. Additionally, drive cables do wear out eventually and need to be replaced.

Blocked or Damaged Filters

Fuel and air filters can get blocked on occasion, which can negatively impact its ability to self-propel or drive. A blocked or damaged air filter can cause your mower’s engine to overheat, preventing it from driving forward or in reverse. A blocked fuel filter prevents enough gasoline from reaching your mower’s engine, which will eventually lead to stalling and render it incapable of any movement.

Transmission Problems

If your lawn mower’s transmission is damaged or failing, it won’t be able to properly change gears, which can prevent your mower from driving forward or backward. Likewise, it can get stuck in one gear limiting your mower’s ability to drive efficiently.

Additionally, leaks in your mower’s transmission fluid reservoir or lines can cause problems shifting gears. Worse yet, if you don’t address the issue, it can eventually lead to significant damage to other engine components like the pistons and valves.

Mower Blades Won’t Engage or Disengage

Occasionally, your lawn mower’s blades will fail to engage. There are a variety of reasons this can happen. And, many of the reasons are unique to particular models. For that reason, you should always check your owner’s manual’s troubleshooting section if you encounter this problem.

When your mower’s blades fail to engage, you will need to check its battery, drive belts, pulley, and check for any obstructions.

Check the Battery

Make sure your battery is fully charged. Riding lawn mowers have a power takeoff clutch mechanism installed that engages the mower’s cutting blades. In some instances, this mechanism is electric, and if your battery is weak, it won’t be able to engage the blades.

If you encounter this problem, check the battery with a voltmeter and put it on a charger if it indicates your battery is too weak. The NOCO Genius One-Amp Automatic Smart Charger is a great option for performing this task.

Check the Belts

Your mower’s power takeoff mechanism works with a drive belt to engage our mower’s blades. That belt is located on the mower’s drive deck and needs to be checked for damage and wear if the blades fail to engage or disengage. If the belt appears to have any problems, you need to replace it.

Check the Pulleys

Your mower has an idler pulley that adjusts the drive belt’s tension. If that pulley gets frozen in place, the blades cannot engage. If the pulley is frozen, you need to replace it. If you have difficulty locating the idler pulley, look for bearings located at its center. Your mower’s other pulleys are attached to a central shaft and not directly to bearings, making the idler pulley easy to pick out from the other ones.

Check for Any Obstructions

Your mower blades can fail to engage if the power takeoff clutch mechanism or the drive belt becomes obstructed by rocks, grass, or other debris. Turn off your mower, disconnect the spark plug cable, and wait until all moving parts halt before looking for obstructions.

Additionally, it is best to wear a good pair of leather work gloves when removing any obstructions you find. Wells Lamont’s Leather Work Gloves with Adjustable Wrist are great for performing this task.

Final Thoughts

Craftsman lawn mowers are designed for heavy use. However, like all machines, they can occasionally break down. By following the instructions detailed in this article, you will be able to resolve many of the issues leading to a situation where your Craftsman mower won’t work.

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