A string trimmer, weed wacker or weed eater (whatever you call it) is a great addition to your lawn care equipment. It provides you with that finished well-manicured look. Well, at least it used to before it stopped working. Now, you can’t even get it to start.
A Shindaiwa string trimmer will not start when the engine isn’t getting the air, fuel, and spark required to start the engine. This can be due to a plugged air filter or fuel filter; clogged fuel line; dirty carburetor; bad spark plug; plugged spark arrestor; and incorrect fuel mix.
Keep reading for a full list of items that can cause a Shindaiwa string trimmer to not start. Before working on your trimmer, stay safe and make sure all moving parts come to a stop; the engine has cooled, and the spark plug boot is disconnected before making repairs.
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Follow all safety instructions provided in your equipment operator’s manual before 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.
Reasons Your Shindaiwa String Trimmer Will Not Start
When you find your Shindaiwa string trimmer won’t start, the best thing to do is rule out the air filter, fuel filter and spark plug as being part of the problem. These are the maintenance items that should be replaced annually to help keep your trimmer running at its best.
Plugged Air Filter
Take a look at the air filter first. A filter is an essential part required to keep dirt from getting to the engine causing wear and damage.
When the air filter is not regularly replaced or cleaned, it can become plugged keeping air from passing through the filter. Without sufficient airflow, your string trimmer can die and won’t start.
Replace a Shindaiwa air filter annually and check it after every 10 hours of operation to make sure it is still in good condition. You will have to check it more frequently in dry dusty conditions.
Replace the filter with a new one when you find the filter is damaged, very dirty, or wet. Remove and clean a dirty filter by brushing the dirt off of the filter or washing it with water and a mild dish detergent. Rinse clean and lay flat to dry.
NEVER run your Shindaiwa string trimmer with a very dirty air filter or without an air filter.
It can be tempting to try to finish your trimming task by removing a plugged filter and running the trimmer while you wait on a new filter replacement. This can allow dirt in the engine and cause permanent damage.
Solution: Remove the filter and wipe out any remaining dirt from the air filter housing and cover. Replace a dirty air filter with a new air filter.
Bad Spark Plug
The spark plug is a maintenance item that should be replaced each year to keep your Shindaiwa string trimmer running at its best. The spark plug will become dirty over time with a buildup of carbon. This can cause the plug to misfire having intermittent starting problems.
You will also need to check the spark plug gap along with any wear or damage to the plug. These items can also prevent your trimmer from starting.
Solution: Before removing the spark plug, wipe around the plug to remove all dirt and debris. Remove the plug and check its condition. Replace a plug that is very dark in color, has signs of wear, or is damaged.
You can attempt to clean a dirty spark plug with a wire brush and reuse it. I prefer to replace it. It is an inexpensive part and one of the primary items responsible for keeping your string trimmer running.
Make sure your spark plug is gapped to the manufacturer’s specification, install the spark plug, and securely attach the spark plug wire (boot).
Plugged Fuel Filter
The fuel filter used on a Shindaiwa string trimmer can be found in the fuel tank. This filter is used to strain fuel before it enters the fuel pick-up tube to keep dirt and debris out of the fuel system.
Just like the air filter, the fuel filter can become plugged when it isn’t changed out regularly. I recommend replacing the fuel filter once a year. If you find your fuel is dirty, you may need to drain the fuel tank, fill it with fresh fuel and replace the fuel filter.
When the fuel filter becomes clogged with dirt, it will restrict the amount of fuel that is able to flow through the filter and into the fuel lines. This can keep your Shindaiwa’s engine from getting the fuel it requires to start and run.
Solution: Locate the fuel filter inside the fuel tank and replace the plugged filter. Replace the fuel if you find it dirty as well.
- Wipe around the fuel cap to remove any loose dirt so it doesn’t fall into the fuel tank once you remove the cap.
- Gain access to the filter. A clean bent wire works well to “fish” the filter and pull it out of the tank.
- Remove the old filter from the fuel line. Be careful not to lose the retaining ring securing the line to the filter.
- Install the new fuel filter securing the fuel line to the filter using the retaining ring.
- Place the filter back inside the fuel tank and reinstall the fuel cap.
Incorrect 2-Cycle Oil Mix
Using straight gas or the wrong ratio of gas to oil mix can damage the engine and cause it to seize up. Straight gas added to your Shindaiwa string trimmer is a quick way to damage the engine. Read more information in “This is the Type of Gas and Oil Shindaiwa String Trimmers Use“.
Shindaiwa 2-Cycle Gas to Oil Mix
A 2-cycle Shindaiwa string trimmer requires a gas-to-oil ratio of 50:1. 50 parts gas needs to be mixed with 1 part oil.
| Mixture | 1 Gallon Gas | 2 Gallon Gas | 2.5 Gallon Gas |
|---|---|---|---|
| 50:1 | 2.6 oz Oil | 5.2 oz Oil | 6.4 oz Oil |
When creating the oil and gas mixture, use unleaded gasoline with a minimum octane rating of 89 (mid-grade) and maximum ethanol content of 10%. Add a 2-cycle premium oil that is ISO-L-EGD and JASO M345 FD certified.
Mix it in an approved gas can before adding it to your string trimmer. Shindaiwa recommends using an ECHO 2-cycle oil like ECHO Power Blend or ECHO Red Armor.
2-Cycle Shindaiwa Premixed Fuel
A great option to reduce fuel problems and extend engine life is using an ethanol-free fuel mix. This is an ethanol-free blend of oil and fuel that is ready to pour into your string trimmer’s fuel tank.
You won’t have to deal with the bad effects of ethanol as discussed in the fuel section. Also, it’s convenient to have fuel available on your shelf when you need it. ECHO Red Armor Premixed is a good option for 50:1 premixed fuel.
Solution: Drain the fuel tank and fill it with the correct gas to oil mix. If you continue to have problems, have a small engine mechanic diagnose the problem and determine whether a cost-effective repair can be made.
If you continue to have problems, have a small engine mechanic diagnose the problem and determine whether a cost-effective repair can be made.
Old Fuel
Old fuel left in a Shindaiwa string trimmer won’t only cause fuel restrictions, but it can also damage the carburetor and engine.
Because ethanol is found in most gasoline and gas begins to break down as soon as 30 days after purchase, it’s important to use fresh gasoline with low ethanol content.
Ethanol is not kind to the small engine used on your Shindaiwa trimmer. This product naturally attracts moisture from the air causing premature corrosion and fuel restrictions.
The ethanol and water mixture not only leaves behind varnish and gummy deposits, but it will also separate from gas over time causing the engine to run extremely hot with this water and ethanol mixture.
Because of this, always use unleaded gasoline with a minimum octane rating of 89 (mid-grade) and maximum ethanol content of 10% (E10). Never use E15 or E85 in the engine as this will damage the engine and most likely void manufacturer warranties.
I know it’s hard to know how quickly you’re going to go through fuel. It’s like trying to anticipate how much rain and sunshine you’ll see that will impact how quickly the grass grows. To keep your fuel system clean and to reduce the negative effects of ethanol, add a fuel stabilizer.
I like Sea Foam Motor Treatment as a fuel stabilizer. Some 2-cycle oils include a fuel stabilizer, but you’ll need to read the details on the oil bottle to determine how long the product will stabilize the fuel.
For example, ECHO Power Blend includes a stabilizer, but it’s good for 30 days. ECHO Red Armor is good for up to 2 years. Don’t assume that just because the oil you use states it includes a fuel stabilizer it will stabilize the fuel for longer than 30 days.
Solution: Drain any old fuel remaining in your string trimmer and fill it with fresh fuel. This is an oil and fuel mixture for the 2-cycle engine on your Shindaiwa trimmer.
Bad Primer Bulb
A cracked Shindaiwa primer bulb that won’t fill up with fuel won’t function correctly to get fuel to the carburetor for starting the string trimmer. If the primer bulb appears in good condition and it still won’t fill, check for a clogged fuel filter or fuel line.
Solution: Replace with a new primer bulb.
Clogged Fuel Line
Old fuel sitting in your string trimmer can leave a gummy sticky deposit behind that restricts fuel flow. This can clog the fuel line and restrict the fuel flow your string trimmer requires to start.
Solution: Replace a fuel line on your Shindaiwa string trimmer when it is cracked, kinked, or clogged.
Plugged Fuel Tank Vent
The fuel tank vent allows air into the tank. Without a vent, the fuel tank will create a vacuum that won’t allow fuel to flow through the string trimmer.
A good indication you may have a fuel tank vent problem is when your Shindaiwa trimmer runs for a few minutes and then shuts down and won’t start until you remove or loosen the fuel cap to allow air into the fuel tank.
When you tighten the cap and allow it to run and the string trimmer dies and fails to start until the cap is loosened, you most likely have a fuel vent problem.
Solution: Replace a plugged fuel vent.
Dirty Carburetor
The carburetor regulates the amount of fuel that is mixed with air to create combustion in the cylinder. Old fuel will gum up and clog the carburetor so it no longer functions properly.
Solution: If you are a little mechanical you should be able to handle cleaning your carburetor. Clean the carburetor by taking it apart and using carburetor cleaner to clean it.
If the carburetor does not function after being cleaned, you may need to rebuild it or replace it with a new carburetor.
Depending on the model and age of the string trimmer you use, the price of a carburetor, and the cost of labor, it may be best to invest in a new trimmer rather than put money towards replacing a carburetor on an old trimmer.
Bad Recoil Starter
Your Shindaiwa string trimmer uses a recoil to start the engine. A bad pulley; loose or missing spring; or broken clips can keep your recoil from working.
Solution: 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 the pulley, you are better off just replacing the recoil assembly.
Plugged Spark Arrestor
You will find a spark arrestor in your Shindaiwa string trimmer that can prevent it from starting. The spark arrestor is a small screen that can get plugged with soot.
Disconnect the spark plug boot. Make sure your engine is not hot. Remove the engine cover and place the piston at Top Dead Center to keep carbon from falling into the cylinder.
Remove the spark arrestor screen cover, gaskets, and spark arrestor from the muffler. Clean the screen with a wire brush to remove the soot. Reinstall.
If you are unable to clean it sufficiently or it is broken or has a hole in it, replace it with a new spark arrestor.
Flooded Engine
I have had customers bring their string trimmer to the repair shop because they can’t get it started. Many times it’s due to a flooded engine which isn’t too serious.
The engine can become flooded when the choke is in the closed position and the starter rope was pulled many times allowing too much gas into the carburetor.
It can also happen with the switch off and the starter rope being pulled multiple times or when the primer bulb is pushed too many times.
Solution: Use the following procedure to “unflood” your string trimmer so the engine gets the correct fuel-to-air ratio required to start and run.
How to Fix a Flooded Engine on a Shindaiwa String Trimmer
- Turn the switch on to the run position.
- Move the choke lever to the run position.
- Press the throttle trigger while pulling the starter rope over and over. This can take anywhere between 5 and 15 pulls before it starts. Your string trimmer engine will sputter first. Continue to pull 2 to 3 more times and it should start.