I am never happy when my lawn mower dies in the middle of my lawn. I’m pretty sure you’re not either unless you are one of those inquisitive people with a lot of extra time and love to tinker with equipment. I just want to get my mower up and running again.
A Honda lawn mower may start and then die when bad fuel clogs the fuel system; a plugged air filter or incorrect choke position restricts airflow; a spark plug or coil is bad, or the mower overheats from an incorrect engine oil level or a plugged mower deck.
I put together this guide to help you get your Honda mower up and running again. Remember to follow the safety guidelines in your owner’s manual before working on your Honda mower.
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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.
12 Reasons Your Honda Mower Starts Then Dies
Bad or Old Fuel
Gasoline that has been sitting in your mower can break down and become less effective as soon as 30 days after purchase. Most types of gasoline on the market today contain an environmentally friendly fuel known as ethanol, a corn-based product.
While ethanol is okay to run in most vehicles, it isn’t good for your Honda small engine. Ethanol attracts moisture from the air which can be corrosive to your fuel system.
As it evaporates, a gummy substance is left behind which can clog the fuel system.
Over time, the ethanol and water mixture will separate from the gasoline and sink to the bottom of your fuel tank. This solution will run hotter in your engine potentially causing engine damage.
Because of the negative effects ethanol can have on your mower, make sure you are using unleaded gasoline with no greater than a 10% ethanol content in your gas-powered mower. Learn more about choosing the right gas for your Honda lawn mower here.
If the gas has been sitting in your mower for a long time, drain the fuel tank using a siphon. Refill with fresh fuel using an additive to stabilize your fuel and reduce moisture.
I add Sea Foam Motor Treatment to all my gas. Learn more about the advantages of using Sea Foam in your mower.
Plugged Air Filter
A plugged air filter can cause your mower to run sluggishly and die. Failing to regularly check and clean your air filter can result in a mower plugged with dirt and debris.
When this happens, the airflow to the engine is restricted. Without proper air, your Honda mower’s engine will shut down.
I recommend replacing your air filter annually and cleaning it several times throughout the mowing season. Follow these instructions to clean your type of Honda air filter:
Clean a Honda mower paper air filter
- Carefully remove the air filter from the filter housing.
- Wipe any dirt out of the housing. Be careful and don’t let any dirt fall into the air intake.
- Tap it against a solid surface to knock it loose and remove as much dirt as you can get out of the filter.
- Check to see if you can see light shine through the paper by holding your filter up to a light source.
- Reuse your filter if you can see light. If not, it’s time to buy a new filter.
- Reinstall the filter and secure the filter housing cover.
Clean a Honda mower foam air filter
- Remove the air filter and wipe out any dirt remaining in the filter housing. Don’t let any dirt fall into the air intake.
- Inspect your filter’s condition. If it is dry, brittle, has brown spots, or is torn, you must replace your filter with a new one. If it is in good condition, proceed with the next step.
- Wash our filter with mild dish soap and water to remove dirt from the filter.
- Rinse until the soap is removed and the water runs clear.
- Lay flat to dry. Placing it outdoors on a sunny or breezy day will help speed up the drying process.
- Once the filter is dry, lightly saturate it with foam filter oil. You want it fully covered with oil, but you don’t want it dripping with oil. If you put too much oil on your filter, squeeze out the excess oil from the filter or use a paper towel to soak up the excess oil.
Plugged Fuel Filter
Check the fuel filter if your Honda mower uses one. The fuel filter is used to strain the fuel before it enters the fuel system and engine.
Gummy substances left from running old fuel in your mower along with dirt can clog the filter not allowing fuel to pass through it.
Replace a plugged fuel filter. When installing a new fuel filter, make sure you pay attention to the arrow on the side of the filter housing.
This arrow must be pointing in the direction of your fuel flow for the filter to work correctly. This means the arrow must be pointed toward the carburetor and away from your fuel tank.
Clogged Fuel Lines
Your fuel lines can become clogged causing a fuel restriction. This will make your Honda mower die and no longer run. Check for blockages by using your fuel shut-off valve or pinch pliers on the fuel line to start and stop fuel flow while checking the lines.
To check a section of the fuel line, stop the fuel flow. Detach the end of a section of the fuel line from the fuel component that is furthest from the fuel tank.
Place the end of the fuel line in a container to catch fuel. Start your fuel flow and check for good flow out of the hose.
If you aren’t getting good flow, shut off the fuel flow and completely remove the section of the hose from the mower. Spray carburetor cleaner in the hose to help loosen up the clog.
Follow this by blowing compressed air into the line to remove the clog. Repeat until the blockage has been removed and reinstall the fuel line and start your fuel flow.
You must replace the line with a new fuel line if you are unable to remove the blockage. It’s also a good time to replace the hose when you find it has become dry and brittle.
Bad Fuel Pump
Your mower will only have a fuel pump on it if the carburetor sits higher than the fuel tank requiring a pump to push fuel to the carburetor.
If you have a push mower and can’t find one, you may not need one. Make sure your fuel pump is working by first making sure you are getting fuel to the pump.
You can confirm this by checking for flow to the inlet port on the pump using the instructions above to check for fuel line clogs. Once you have confirmed you are getting flow to the pump, stop fuel flow and remove the fuel line connected to your carburetor.
Place it in a container to catch fuel. Start your fuel flow and start your mower. Watch the fuel coming from the fuel line into the container. It should give you a steady or pulsating flow of fuel. If it does not, replace your fuel pump.
The carburetor regulates the amount of gas mixed with air that is allowed into the cylinder to form combustion. When the carburetor gets dirty and components of your carburetor get stuck or clogged, it is no longer able to regulate the fuel.
To narrow down the problem of your Honda mower not running due to the carburetor, check out these things first:
- Confirm you are getting fuel to the carburetor. Check the fuel line going to the carburetor for good flow.
- Remove the air filter from the filter housing.
- Spray carburetor cleaner into the air intake and start your mower.
- If your Honda mower starts, runs fine, and then shuts down, there is a good chance the problem lies in the carburetor.
To clean your carburetor, follow the instruction in this guide. If you prefer to have someone else do this for you, bring your mower to a small engine mechanic to have cleaned or rebuilt if needed.
Insufficient Engine Oil Level
The engine crankcase must always be filled to the manufacturer’s recommended oil level. This is not just a suggestion. Having too little oil or too much oil in the crankcase can be very damaging.
Engine Oil Level is Low
The engine oil’s purpose is to lubricate the engine’s internal components so the parts move freely. When there isn’t enough oil, friction will increase building heat in the engine.
This heat can become so hot, it begins burning oil and melting internal engine parts.
When you run your Honda mower and it shuts down because of a lack of oil, you most likely have caused engine damage.
You can attempt to add oil and bring it to the correct level, but a mower that overheats and shuts down from a lack of oil most likely will not be solved with this simple fix.
When you experience this problem, have a small engine mechanic diagnose the damage and provide you with an estimate to repair the engine if it is repairable.
Take into consideration the estimate, the age of your mower, and the price of a replacement mower when deciding whether to repair or replace your Honda mower.
Too Much Engine Oil
Many mower owners are aware of the disadvantages of not having enough engine oil in their mowers, but they don’t always know it’s not good to have too much oil in the crankcase. Too much oil will cause increased pressure in the crankcase.
This can cause the engine to overheat and shut down when the crankshaft and rod must push through extra oil. It can also cause the engine to become hydro-locked when oil gets into the cylinder.
Find out more information about the damage of running too much oil in your engine here.
Bad Spark Plug on Your Honda Mower
A spark plug can become dirty and foul out. Carbon buildup on the tip of the spark plug can cause your Honda mower to not spark causing your mower to die.
Remove your spark plug and clean the tip. Replace it with a new plug if the tip is very dark or the spark plug has a burnt electrode or cracked porcelain.
In addition to checking the spark plug condition, ensure the plug is gapped according to the manufacturer’s specifications.
Make sure the spark plug wires are also secure. These two items can also contribute to the mower’s running problem.
Bad Ignition Coil
The winding on the ignition coil can separate and short out when your mower is hot. When this happens, the spark plugs are unable to get the voltage they need to create spark. This can cause your mower to die after it’s been running for a while.
Identify a bad ignition coil using an ohmmeter to check for a break in continuity. Replace the ignition coil if you find there is a break.
Choke is in the Wrong Position
The choke restricts the amount of air your engine receives, therefore allowing more fuel into the combustion chamber. This is needed to start your engine when it is cold.
However, if you leave the choke in that position after the engine heats up, the Honda mower will die.
Bad Gas Cap
If your mower runs for a while and then shuts down, the problem could be in your gas cap. The gas cap on your Honda mower is vented to allow air to pass through the cap.
When the vent becomes plugged, a vacuum is formed in the fuel tank that prevents fuel from flowing out of the tank. You can try to identify whether you have a bad or plugged fuel cap by allowing your mower to run for a while with and without your fuel cap.
If it runs fine without the cap and then shuts off after some time with the fuel cap on, you most likely have a fuel cap problem.
You can attempt to clean the fuel cap to unclog the vent. The fuel cap must be replaced if you are unable to fix the cap.
Plugged Mower Deck
When you don’t scrape your mower deck regularly, grass clippings and dirt can build up under the deck. Not only will this give you a bad cut, but it will put extra strain on your engine causing it to become hot, experience a power loss, and possibly die.
The engine must work much harder to rotate the blades through the packed deck.
Keep your mower deck clean on your Honda mower by scraping it regularly. Keep your mower blades sharp. A dull mower blade will only magnify the problem and put the engine under additional strain to cut through the debris in the deck.
Still Need Help Identifying Your Honda Mower Problem?
There are so many things that can go wrong with a lawn mower. If this information doesn’t provide you with tips needed to fix your Honda mower, check out the article below. This is a guide listing many common problems that can develop in your Honda mower.