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HomeRepair HelpRyobi Mower RepairRyobi Lawn mower won't start Repair
Ryobi Lawn mower won't start
If your Ryobi lawn mower won't start, start with the basics that fail most often: the spark plug, a clogged carburetor, stale fuel, the start switch, and then the fuel pump. A worn or fouled spark plug can keep the engine from firing at all, so inspect it for carbon buildup, a cracked insulator, or damaged electrodes, and confirm spark with a spark plug tester. If the plug checks out, the next likely issue is a carburetor clogged by old gasoline left sitting in the mower. Sticky fuel residue in the carburetor or float bowl can block fuel flow and leave you with a lawn mower not starting, even if the rest of the engine is in good shape. Try carburetor cleaner first, then a carburetor repair kit or full carburetor replacement if needed. A bad start switch can also stop a push mower from starting, and a weak fuel pump or contaminated pulse line can prevent fuel delivery. If your Ryobi lawn mower has spark but won't start, enter your model number on RepairClinic.com to find the exact spark plug, carburetor, start switch, fuel pump, or other replacement part that fits your mower.
01 - Ryobi 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 - Ryobi 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 - Ryobi 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 - Ryobi Lawn Mower Start Switch
To determine if the start switch is defective, use a multimeter to test it for continuity.
Highly Likely
06 - Ryobi 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 Ryobi lawn mower start if it has fuel?
My Ryobi 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 Ryobi lawn mower?
Can old gas keep a Ryobi push mower from starting?
How do I find the correct spark plug, carburetor, start switch, or fuel pump for my Ryobi lawn mower?
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