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HomeRepair HelpHonda Mower RepairHonda Lawn mower won't start Repair
Honda Lawn mower won't start
If your Honda lawn mower won't start, start with the basics that fail most often: the spark plug and the carburetor. A worn or fouled spark plug can keep a Honda mower from firing at all, and a spark plug tester is the quickest way to confirm whether you have a strong spark while the engine is cranking. If the plug checks out, the next most likely problem is a clogged carburetor caused by stale fuel or old gas left sitting in the carburetor float bowl. In many cases, cleaning the carburetor with carburetor cleaner will get a lawn mower not starting again, but sometimes you will need a carburetor repair kit or a full carburetor replacement. Bad gasoline itself is another common reason a Honda push mower won't start. After that, check the start switch for continuity and inspect the fuel pump, especially the pulse port line, diaphragm, and check valves. Whether your lawn mower has spark but won't start or the engine will not turn over properly, enter your model number on RepairClinic.com to find the exact Honda replacement part that fits your mower.
01 - Honda Lawn Mower Spark Plug
Inspect the spark plug for signs of wear or damage. If the porcelain insulator is cracked, an electrode is burned away or damaged, or there is heavy carbon buildup at the electrode, replace the spark plug. To determine if the spark plug is defective, use a spark plug tester. You should see a strong spark between the tester’s terminals when the engine is cranking. If there is no spark, this indicates that the spark plug is defective and should be replaced.
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02 - Honda Lawn Mower Carburetor
The carburetor might be clogged. A clogged carburetor is most commonly caused by leaving fuel in the lawn mower for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the carburetor and prevent the engine from starting. If the carburetor is clogged, try cleaning it with carburetor cleaner. If cleaning the carburetor isn’t effective, rebuild or replace the entire carburetor.
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03 - Honda Lawn Mower Carburetor Repair Kit
The carburetor might be clogged. A clogged carburetor is most commonly caused by leaving fuel in the lawn mower for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the carburetor and prevent the engine from starting. If the carburetor is clogged, try cleaning it with carburetor cleaner. If cleaning the carburetor isn’t effective, rebuild or replace the entire carburetor.
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04 - Old or Bad Gasoline
There may be old or bad fuel in the carburetor float bowl. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the carburetor and prevent the engine from starting. If the carburetor is clogged, try cleaning it with carburetor cleaner. If cleaning the carburetor isn’t effective, rebuild or replace the entire carburetor.
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05 - Honda Lawn Mower Start Switch
To determine if the start switch is defective, use a multimeter to test it for continuity.
Highly Likely
06 - Honda Lawn Mower Fuel Pump
The fuel pump has three ports: the gas in port, the gas out port, and the pulse port. The pulse port is connected to the engine crankcase by a small rubber tube. As the engine runs, air inside the crankcase alternately pressurizes and depressurizes the air in the tube. This pressurized air moves a diaphragm inside the pump and pumps the gas. If the engine oil is overfilled, oil can enter the pulse port line, preventing it from working properly. The fuel pump also has two small check valves on the input and output ports. The check valves prevent fuel from reentering the gas tank. These check valves can fail. To determine if...
Highly Likely
Frequently Asked Questions
Why won't my Honda lawn mower start?
My Honda lawn mower has spark but won't start. What should I check next?
How do I know if the start switch is bad on my Honda lawn mower?
Can old gas keep a Honda push mower from starting?
How do I find the right spark plug, carburetor, or fuel pump for my Honda lawn mower?
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