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13 Reasons a Kawasaki Engine Won’t Start: Troubleshooting

When trying to identify the reason your engine isn’t starting, look for items that can keep the engine from getting fuel, air, and spark. Without these three requirements, the engine won’t start and continue to run.

A Kawasaki engine won’t start due to a bad spark plug, clogged fuel line, clogged air filter, bad fuel pump, plugged fuel filter, dirty carburetor, bad starter solenoid, faulty switch, or wrong choke setting.

Keep reading for additional Kawasaki starting problems. Always remove the ignition key and spark plug wires before performing repairs.

Kawasaki engine

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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.

This is Why a Kawasaki Engine Won’t Start

1. Wrong or Old Gas

Right Gas

Old gas is often the main culprit when a Kawasaki engine begins running sluggishly, having starting problems, or dying after it’s been running.

You’ll find ethanol in most gasoline today. This is an alternative fuel, often made from corn, to make fuel more environmentally friendly.

Ethanol naturally attracts moisture to the gas which isn’t good for the fuel system or engine. The water and ethanol mixture not only separates from gas and sinks to the bottom of the fuel tank, but it also leaves behind varnish.

As a result, parts will begin to degrade and restrictions develop in the fuel system.

Because ethanol has negative effects on an engine and fuel system, always use gas with low ethanol levels or fuel that is ethanol-free. Gas with high ethanol levels can cause significant engine damage.

Use an unleaded gas with a minimum 87-octane rating and maximum 10% ethanol content. Stay away from fuel sold as E15 and E85 as these contain ethanol amounts up to 15% and 85%.

Only Use Fresh Gasoline

Because gasoline begins to break down and becomes less effective as soon as 30 days, it is important to purchase gas and consume it within this time.

If you purchased more gas than you can consume within 30 days, use a fuel additive like Sea Foam Motor Treatment to stabilize the gas so it lasts a little longer.

I love this product! I actually add it to the fuel for all of my small engine products as added protection to the fuel system and engine.

This is a product that must be added to gas while the gas is still fresh. It cannot reverse the effects of old fuel. Read more about the advantages of adding Sea Foam to the fuel tank here.

SOLUTION: When you find you filled the fuel tank with the wrong fuel or the fuel is old, you must drain the fuel tank. A manual siphon pump is an inexpensive tool that works well to drain the tank.

Add fresh gas and a fuel additive to clean the fuel system, reduce moisture, and stabilize the fuel.

2. Plugged Fuel Filter

You will find a fuel filter inserted between the fuel lines to keep dirt from entering the fuel system. When the filter becomes plugged because it isn’t regularly replaced, the amount of fuel that passes through the filter is reduced.

The engine may not receive enough fuel for combustion. The fuel filter is a maintenance part that should be replaced annually.

SOLUTION: A clogged fuel filter must be replaced with a new one. Make sure you install it correctly with the arrow on the filter pointed in the direction of the fuel flow.

3. Clogged Fuel Line

The sticky deposits left behind by old fuel can get stuck in the fuel lines. This narrows the opening in the line restricting fuel flow.

I’ve also seen things like pine needles and plastic shavings from new fuel tanks clog the fuel lines causing an engine not to start.

SOLUTION: Once you find a clogged line, try to remove the blockage. To do this, remove the line from your Kawasaki.

Spray carburetor cleaner into the line to try to loosen the blockage. Follow the carb cleaner with compressed air blown into the line to remove the clog.

If you are unable to dislodge the clog, Purchase a new fuel line making sure you get the right diameter and length of the fuel line.

4. Bad Fuel Pump

The fuel pump on your mower may be causing it to not start. The function of the fuel pump is to work against gravity to move fuel to the carburetor.

When it fails, the carburetor doesn’t receive the fuel it needs and the engine is unable to start. A carburetor failing due to old fuel is common.

Many mowers use a vacuum-style fuel pump to get fuel to the Kawasaki engine. Over time, fuel can cause your fuel pump to degrade.

For a pump that is no longer able to use the engine vacuum to draw fuel out of the fuel tank so it gets to the carburetor, the pump must be replaced.

If the fuel pump is leaking fuel, you must replace it. When you can’t see any visible signs of damage to your pump, perform a couple of tests to identify a pump problem:

  • Shut off your fuel supply using the fuel shut-off valve under your fuel tank or use clamps to pinch the fuel line to stop the flow.
  • Remove the hose from the inlet port on the pump. Place it in a container placed lower than the fuel tank so fuel can flow into the container using gravity. This step is to confirm your fuel pump is getting the fuel.
  • Start your fuel flow. If you are getting flow into the container, you have confirmed you are getting fuel flow to the pump. If you are not, you have a fuel restriction you need to locate prior to the pump.
  • Shut off the fuel flow. Replace the hose on the inlet port.
  • Remove the hose from the carburetor and place it in a container so you can confirm the condition of your fuel pump.
  • Start your fuel flow and start your engine. Watch for a steady or pulsating flow of fuel out of the fuel line.
  • Once your test is done shut off your mower and reattach your fuel hose to the carburetor.

Consult your operator’s manual for pressure specifications for other types of fuel pumps.

SOLUTION: Replace the Kawasaki fuel pump if you are not receiving a constant or pulsating flow out of the pump.

5. Dirty Carburetor

A dirty carburetor can be the reason your Kawasaki engine will not start and run. When the carburetor can’t regulate the amount of fuel that is mixed with air the engine will fail to start.

Old fuel often plays a role in a carburetor failure. This is because old fuel clogs the fuel passages restricting fuel flow. It can also leave behind varnish that causes internal parts to stick and no longer function.

When your carburetor does not work properly, you will have to clean the carburetor and replace any stuck or damaged parts that are unable to be cleaned.

SOLUTION: I have listed steps for cleaning your Kawasaki carburetor here. Follow these if you have a little mechanical ability and are comfortable working with small parts.

If you do not want to attempt cleaning or rebuilding your carburetor, you can take your mower to your small engine repair shop to be cleaned or you can replace it with a new carburetor assembly.

6. Bad Spark Plug

Fouled spark plugs or plugs with broke porcelain or worn electrodes can cause intermittent spark issues that may prevent the engine from starting.

Check your spark plug to ensure they are in good condition. Make sure the spark plug wires are securely attached and the electrode gap is set to the manufacturer’s specifications.

SOLUTION: Remove your spark plug and inspect it for signs of carbon buildup or a cracked porcelain insulator. Replace with a new spark plug(s) if they are damaged, worn, or very dark in color.

If the spark plug(s) is in good condition, clean the tip with a small wire brush. Make sure the spark plugs are correctly gapped and the wires are secure.

7. Plugged Air Filter

An air filter is installed on your mower to keep dirt from entering the air intake and wearing the engine. When the filter isn’t cleaned regularly or replaced, airflow is restricted and the engine may not start.

I recommend replacing the air filter annually and checking its condition regularly through the mowing season. You’ll have to check it more often if you use your mower in dry dusty conditions.

If you find the filter is in good condition, clean it. However, if it is very dirty or damaged, it’s best to replace it with a new one.

SOLUTION: Check and clean the air filter. If the air filter is so bad that it’s keeping your Kawasaki engine from starting, you should install a new one.

Clean a Kawasaki PAPER air filter:

  • Remove the air filter from the filter housing.
  • Don’t let any dirt fall into the air intake. Wipe out any excess dirt that remains in the filter housing and filter cap with a dry cloth.
  • Tap the air filter against a solid surface to knock as much dirt loose as possible and allow it to fall out of the filter.
  • Hold the filter up to a light source and check for light shining through the paper element.
  • Reuse the filter if you can see light. Replace your filter with a new filter if you cannot see good light, it is extremely dirty, or the filter is damaged.
  • Install the air filter.

8. Loose Cables or Corroded Terminals, Wiring, or Components

There can be a break in continuity when the battery cables, wiring, and electrical components are loose or corroded.

SOLUTION: Remove any corrosion you find. To do this, disconnect the battery and remove the corroded components.

Use a baking soda solution (2 cups of water mixed with 3 heaping tablespoons of baking soda) to remove the corrosion along with a small metal brush.

Then, make sure all wiring and components are securely installed making good connections.

9. Weak or Bad Battery

When the battery is weak or dead, it won’t provide the power needed to turn over the engine. You’ll need to charge a weak battery and replace it with a new one if it isn’t able to hold a charge.

SOLUTION: Test your battery using a multimeter. If your reading is less than 12.7 volts, place your battery on a battery charger. Read this article for steps and items needed to charge a battery.

10. Bad Safety Switch

The equipment you use has safety switches installed to keep the operator safe. A safety switch can be defective and cause your engine to fail to start.

Consult your operator’s manual to find the safety switches installed on your equipment. For example, items like the seat switch, brake switch, and PTO switch can prevent a lawn mower engine from starting.

SOLUTION: Test your switches using a multimeter. You can also temporarily bypass a safety switch to identify a bad switch but only do this for troubleshooting purposes.

Never operate equipment without the safety switchNever run equipment when a safety switch is bypassed. A safety switch can save you from serious injury and you never know when you’re going to need it.

11. Bad Ignition Switch

The ignition switch could be the problem when you insert the key and find it fails to start.

Check the switch using a multimeter to check continuity to determine if the ignition switch is the problem. To do this, look for the prongs mark B for Battery and S for Starter Solenoid.

Insert the key and turn it to the start position. With the multimeter set to measure resistance, touch one probe to the B prong and the other probe to the S prong.

A good ignition key switch will measure resistance near 0 ohms. A bad ignition key switch will measure infinite resistance and will need to be replaced.

SOLUTION: Replace the ignition switch if it is bad.

12. Bad Starter Solenoid

A Kawaski starter 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 solenoid may be bad is when a wire attached to your solenoid gets hot and begins to smoke or melt.

SOLUTION: Test your Kawasaki solenoid by following the steps here. Replace your solenoid if it is found to be bad.

13. Incorrect Starting Procedure / Wrong Choke Setting

There are several starting procedures you will need to follow in order to start your engine.

Check the Choke Setting

The choke is used to restrict airflow when starting a cold engine. When the choke lever isn’t in the right position, the equipment can fail to start.

  • Starting a cold Kawasaki engine:
    • Place the choke lever in the full choke position.
    • Place the throttle halfway between slow and fast throttle positions.
    • Turn the key to the start position and then release it once the engine starts.
    • Adjust the choke lever to the off position.
    • Allow the engine to idle at half throttle for a few minutes before adjusting to full throttle to begin mowing.

Ensure you are following the steps of the safety interlock system:

The safety interlock system is designed to keep you safe. Your Kawasaki won’t start if you don’t satisfy the safety requirements required to use the equipment.

Check these safety measures are met to start the riding mower, zero-turn, or tractor:

  • Sit in the operator’s seat.
  • The brake is on.
  • The PTO is off.

SOLUTION: Follow the steps above to start your Kawasaki engine. This includes following the safety starting procedures and having the choke in the correct position.

Consult your owner’s manual for specific information on your mower.