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HomeRepair HelpLawn Boy RepairLawn Boy Lawn mower won't start Repair
Lawn Boy Lawn mower won't start
If your Lawn Boy lawn mower won't start, start with the most common failure points before assuming the engine has a major problem. A worn or fouled spark plug is the first thing to check, and a spark plug tester will tell you quickly if the plug is producing a strong spark while the engine is cranking. If ignition checks out, the next likely issue is a clogged carburetor caused by stale fuel, or old gasoline left sitting in the carburetor float bowl long enough to leave sticky deposits behind. In many cases, cleaning the carburetor with carburetor cleaner will get a Lawn Boy mower not starting again, but if not, a carburetor repair kit or complete carburetor replacement may be the fix. If your lawn mower has spark but won't start, bad fuel is still high on the list. After that, check the start switch for continuity and inspect the fuel pump, including the pulse port line, diaphragm, and check valves. Whether your Lawn Boy push mower won't start or your lawn mower won't start after storage, enter your model number on RepairClinic.com to find the exact replacement part that fits your mower.
01 - Lawn Boy 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 - Lawn Boy 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 - Lawn Boy 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 - Lawn Boy Start Switch
To determine if the start switch is defective, use a multimeter to test it for continuity.
Highly Likely
06 - Lawn Boy 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 Lawn Boy lawn mower start?
My Lawn Boy mower has spark but won't start. What should I check next?
How do I tell if the start switch is bad on my Lawn Boy mower?
Can old gas keep a Lawn Boy push mower from starting?
How do I find the right spark plug, carburetor, or fuel pump for my Lawn Boy mower?
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