13 Causes Why a Craftsmen String Trimmer Won’t Turn On

If the Craftsman Weedwacker string trimmer has a clogged air filter, a faulty spark plug, a filthy carburetor, a faulty starting recoil, a clogged fuel filter, a blocked spark arrestor, the incorrect gasoline, the incorrect oil, old gas, or a flooded engine, it will not start. Other potential causes include having the wrong gasoline, the incorrect oil, old gas, or having a flooded engine.

Keep reading to learn about some more probable reasons of the starting problems you’re experiencing with your Craftsman. If you want to avoid being wounded while you’re working on your string trimmer, make sure to take extra precautions and follow all of the safety procedures that are outlined in the operator’s manual.

Internal combustion engines with two cycles and four cycles are the subject of discussion on this page.

In spite of the fact that the vast majority of the Craftsman string trimmers now available on the market are driven by engines with two stages and two cycles, the manufacturer has also produced models with four cycles. Consult the operator’s manual if you are unsure about the kind of engine that is operating your string trimmer if you are unsure about the type of engine that is powering your string trimmer.

outdoorstip craftsman string

Why Your Craftsman String Trimmer Won’t Start and What You Can Do About It

Checking the fuel filter, spark plug, and air filter should be the first thing you do if you are having difficulties starting your Craftsman. These are the kinds of items that need to be updated on a regular basis, and the normal homeowner need to do so at least once a year.

1. Installed a Craftsman String Trimmer’s Air Filter and Plugged It In

The air filter is essential because it stops dirt and debris from entering the engine’s air intake, which would otherwise lead to wear and damage if it were allowed to do so.

It is essential to ensure that the filter is kept clean because, if it becomes clogged, it will begin to restrict the volume of air that is able to pass through it. If you maintain a clean filter, then you won’t have to worry about this happening. It’s conceivable that the Craftsman engine isn’t receiving enough airflow, which would prevent it from starting and keeping it going.

If you want to get the job done while you are waiting for the replacement of the air filter, it is not a good idea to operate the string trimmer without the filter. Because of this, the engine could become damaged, and as a result, you can find yourself in a position where you need to purchase a brand-new Craftsman string trimmer to fix the problem.

SOLUTION: Take out the filter, and then use a clean rag to remove any leftover debris from the housing of the air filter. Switch out a soiled filter with a clean one using a fresh air filter.

2. A Craftsman String Trimmer that has a Defective Spark Plug

Spark plugs are susceptible to wear and the accumulation of carbon, which may make them seem unclean. This may cause the plug to misfire, which will prevent it from starting.

The inability of a Craftsman to start might also be due to a spark plug wire that is not securely fastened or an improperly gapped plug.


Take out the spark plug and check the state of the spark plug. It is necessary to replace a spark plug if it is severely corroded, broken, or worn.

A wire brush may be used to make an effort at cleaning a filthy spark plug so that it can be reused. It is better for me to replace it. It is a relatively affordable component, yet it is one of the major elements that ensures your string trimmer continues to function properly.

You need to check that the gap on your spark plug is set according to the manufacturer’s specifications and that the spark plug wire’s boot is fastened firmly.

3. Plugged Fuel Filter in a Craftsman String Trimmer

A small fuel filter that is shaped like a cylinder will be found tucked away within the gas tank of the vehicle. There is some kind of connection between the fuel line and the filter.

Its job is to stop dirt and debris from getting into the fuel system, where they may otherwise clog the carburetor or the fuel line and make it impossible for gasoline to flow properly. Also, this eliminates the possibility of dirt getting into the engine.

When the gasoline filter becomes clogged, either because it is not replaced on a regular basis or because you are using the vehicle with unusually dirty fuel, the amount of fuel that is able to pass through the filter is reduced. This may happen for one of two reasons.

When it isn’t getting the required amount of fuel, the engine in your Craftsman string trimmer may have problems starting as a result.

SOLUTION: Within the gasoline tank, you will find the fuel filter that has to be replaced.

  • Before removing the gasoline cap, clean the area immediately around it to eliminate any dust or debris that might potentially enter the tank.
  • Get permission to use the filter. Hooking the gasoline line with a clean wire that has been bent works nicely in order to remove the filter from the tank.
  • It is necessary to remove the old filter from the fuel line.
  • Replace the old fuel filter with the new one.
  • After that, replace the gasoline tank cap and make sure the filter is properly positioned within the tank.

4. Incorrect Blend of Oil for a 2-Cycle Engine on a Craftsman String Trimmer

If you put unleaded gasoline in a Craftsman string trimmer with a two-cycle engine, you will cause the motor to freeze up and suffer damage. If you add pure gas to your string trimmer, you will quickly render it ineffective.

Gasoline and oil are combined at a ratio of 40:1 in order to power a Craftsman string trimmer with two cycles. In this recipe, 40 parts gas and 1 part oil are combined.

Use unleaded gasoline with a minimum octane rating of 89 (mid-grade) and a maximum ethanol concentration of 10% when you are making the oil and gas combination for your Craftsman string trimmer. This will ensure that the trimmer runs smoothly. Including a 2-cycle premium oil that has certifications from both ISO-L-EGD and JASO M345 FD.

Before adding it to your string trimmer, you should first mix it in a gas can that has been certified. You are able to make use of the Craftsman Complete Synthetic Engine Oil for 2-Cycles.

SOLUTION: First, the fuel tank should be drained, and then it should be refilled with the appropriate ratio of gas to oil. If the issue persists, have a technician that specializes in repairs for small engines analyze the problem and decide whether or not it can be fixed in a way that is economical.

On this page, you can discover further information regarding the kind of gas that should be used in your Craftsman string trimmer.

2-Cycle Premixed Fuel

Using a gasoline blend that does not include ethanol is a fantastic choice that may cut down on fuel-related issues and increase the life of an engine. This oil and gasoline mixture does not include any ethanol and is already prepared to be poured into the fuel tank of your string trimmer.

You won’t have to worry about the negative consequences of ethanol, which were addressed in the section about gasoline earlier. When you need it, having gasoline already on hand on your shelf is not only helpful but also handy. TruFuel also offers a decent 40:1 premixed fuel.

Craftsman Gas to Oil Mixer for 2-Cycle Engines

Mixture1 Gallon Gas2 Gallon Gas2.5 Gallon Gas
40:13.2 oz Oil6.4 oz Oil8.0 oz Oil
Craftsman Gas to Oil Mixer for 2-Cycle Engines

5. A Craftsman String Trimmer with a 4-Cycle Engine That Has the Incorrect Oil or Not Enough of It

If you have a Craftsman string trimmer that has a 4-cycle engine, then it will have two different fill ports: one for the engine oil, and the other for the gas. Y

While working with this particular sort of engine, never combine the gasoline and oil together. It is essential to use the appropriate quantity of engine oil as well as the suitable kind of engine oil.

Never put 2-cycle engine oil in a Craftsman string trimmer that has a 4-cycle engine. While using the string trimmer, Craftsman suggests using motor oil with an SAE30 rating. This engine oil manufactured by Kawasaki performs well.

To properly lubricate the moving parts of the engine, you need to use oil. If you use the incorrect kind of oil or not enough of it, friction will build up in the engine, which will cause it to overheat, which will prevent the string trimmer from starting and may permanently damage the engine.

SOLUTION: Remove the old oil from the engine, then replace it with the appropriate quality of oil. While using your trimmer in very cold or extremely hot conditions, you may need to change the viscosity so that it corresponds to the temperature of the surrounding environment.

If the issue persists, have a technician that specializes in repairs for small engines analyze the problem and decide whether or not it can be fixed in a way that is economical.

Engine Oil for the Craftsman Four-Cycle String Trimmer

Engine Oil for the Craftsman Four-Cycle String TrimmerSAE30

6. Using Outdated Gasoline in a Craftsman String Trimmer

If you leave stale gasoline in a Craftsman string trimmer, it will not only reduce the amount of fuel that can be used, but it will also cause the carburetor and the engine to get damaged. As soon as thirty days after purchasing, gasoline may start to deteriorate and lose its quality.

The majority of forms of gasoline include ethanol, which is a component that draws moisture from the surrounding air. The combination of ethanol and moisture in this mixture causes the fuel system to get gummed up and corrodes the components.

Since gasoline may start to get stale as soon as 30 days after it has been purchased, the fuel has to be used up within this window of time. If you do not anticipate using it within this period of time, you should stabilize the gasoline by adding a fuel additive in order to make it last a little longer.

Always be sure you use unleaded gasoline that has a minimum octane rating of 89 (which is considered to be mid-grade) and a maximum ethanol level of 10%. (E10). Never put E15 or E85 in the engine since doing so may cause damage to the engine and will likely invalidate any warranties provided by the manufacturer.

SOLUTION: When you have used all of the gasoline that is currently in your string trimmer, you should refill it with new fuel. This oil and fuel combination is suitable for use in a two-cycle engine, whereas unleaded gasoline should be used in four-cycle engines.

To stabilize the gasoline and minimize the amount of moisture that is present in the fuel, use a fuel stabilizer such as Sea Foam Motor Treatment or STA-BIL.

7. A Craftsmen String Trimmer with a Malfunctioning Primer Bulb

If the priming bulb on your Craftsman string trimmer is broken and won’t take in gasoline, it won’t operate correctly and won’t be able to give fuel to the carburetor, which will prohibit the string trimmer from starting. If the priming bulb is broken, the string trimmer won’t be able to start.

SOLUTION: Check to see that the gasoline line is hooked to the priming bulb in a safe and secure manner. If you discover that it is broken or that the priming bulb is shattered, you should switch it out for a brand new one.

8. A Craftsman String Trimmer Suffering from a Blocked Fuel Line

Your string trimmer’s gasoline tank may get clogged with a gummy, sticky residue if you let it sit for a long time if you use old fuel. This might cause the fuel line to get clogged and impede the flow of gasoline, making it difficult for your string trimmer to start.

SOLUTION: If the fuel line on your Craftsman string trimmer has broken, kinked, or become blocked, you will need to replace it.

9. Blocked Fuel Tank Vent in a Craftsman String Trimmer

Since it has a vent built into it, the gasoline tank has the potential to let air into it. A vacuum will be produced within the fuel tank if the fuel tank does not have a vent, which will prevent gasoline from flowing through the string trimmer.

If your trimmer starts up, runs for a few minutes, then shuts off, and won’t start again unless you remove or loosen the fuel cap to let air into the fuel tank, this is a strong indication that there may be a problem with the fuel tank vent. If your trimmer won’t start again unless you remove or loosen the fuel cap, the problem may be with the fuel tank vent. If this keeps happening to you, the fault can be with the vent on the gasoline tank.

You may try to duplicate the problem and establish whether or not it was caused by a blocked vent by pushing the cap closer to the string trimmer while letting it run. If it stops operating entirely and won’t turn over until the cap is removed, the problem most likely resides in the fuel vent. In this scenario, the cap has to be unfastened.

SOLUTION: With a Craftsman string trimmer, the tank releases excess pressure via the fuel lid. It’s time to change the gasoline cap.

10. The carburetor of a Craftsman string trimmer was covered in dirt

Prior to the beginning of the combustion process, the carburetor is the component that is in charge of regulating the amount of fuel that is mixed in with the air that is contained inside the cylinder. Due to the accumulation of old fuel, the carburetor will get gummed up and blocked, which will prohibit it from working properly.


If you have any mechanical ability, you should have no problem taking care of the cleaning of your carburetor. Carburetor cleanser should be used after the device has been disassembled and reassembled in order to be cleaned.

If, after being cleaned, the carburetor still does not perform properly, you will either need to repair it or buy a new carburetor to replace it.

It is possible that it might be more cost effective to purchase a brand new Craftsman string trimmer rather than spend money on the replacement of the carburetor on an older trimmer, but this would depend on the type of string trimmer that you use and the price of a carburetor.

11. A Craftsman String Trimmer Suffering from a Defective Recoil Starter

The engine of your Craftsman string trimmer is started with the help of a recoil. Your recoil may not function properly due to a faulty pulley, a spring that is too loose or missing, or damaged clips.

SOLUTION: You have the option of replacing the spring and restringing the recoil mechanism. If it does not function because other components in your recoil, such as the clips or the pulley, are broken, it is best to simply replace the recoil assembly rather than trying to repair the individual components.

12. A Craftsman String Trimmer with a Defective Spark Arrestor

Your Craftsman string trimmer is equipped with a spark arrestor that may stop it from starting in the event that it is accidentally triggered. A little screen serves as the spark arrestor, and it is susceptible to being clogged with soot.


Make sure the spark plug boot is removed from the spark plug. Inspect to check that the engine does not have a temperature that is too high. Take off the cover for the engine, as well as the cover for the exhaust on the engine.

To get rid of the soot, remove the spark arrestor from its housing, clean it with a wire brush, and then replace it in its original position. If you are unable to clean it to an acceptable degree, if it is broken, or if it has a hole in it, you should obtain a new spark arrestor and use it instead of the one you have now.

13. A Craftsmen String Trimmer That Was Submerged in Water

It is possible for the engine to get flooded if the choke is set to the closed position, the starting rope has been pulled many times, and this allows an excessive amount of fuel to enter the carburetor. While the choke is in the closed position, this occurrence takes place.

In addition, it is possible for it to occur when the switch is off, the beginning rope is pulled several times, and the priming bulb is pushed an excessive number of times. Finally, it is possible for it to occur when the switch is off and the starting rope is pulled numerous times.

SOLUTION: Follow the steps below to “unflood” your string trimmer and ensure that the engine receives the ideal ratio of gasoline to air that is necessary for it to start and continue operating.

How to Repair a Flooded Engine on a Craftsman String Trimmer

  • To start the engine without the choke, move the lever to the run/off position.
  • When you are drawing the starting rope repeatedly, you should press the trigger for the throttle. The number of pulls required to get this going might range anywhere from 5 to 15. Your Craftsman string trimmer’s motor will splutter before it stops completely. Keep pulling it and give it a couple more tries; it ought to start now.