Common Causes of a Hard-to-Start Small Engine
If your small engine is hard to start, here are the top 3 most probable causes: a defective spark plug, a clogged carburetor, and a faulty ignition coil.
Inspecting and Troubleshooting
Inspect the spark plug first when troubleshooting a hard-to-start engine. Look for signs of wear on the electrodes and ceramic insulator. Check for correct gap spacing while the plug is out. If the plug shows damage or the gap is too wide, replace it with a new one.
A clogged carburetor often stems from stale fuel gumming up the jets and passages. Remove the bowl and spray carburetor cleaner through all orifices. Compressed air can help clear debris as well. Proper cleaning typically restores function.
Use an ignition tester to check coil operation if the plug and carburetor verify OK. No or low tester readings indicate it’s time for a new coil. Weak sparks prevent proper ignition even with good compression and fuel.
Starting Techniques
Set the throttle to high revs or the choke position. If the engine has a manual choke, turn it on. Press the primer button (if fitted) about eight times. Pull the starter rope quickly, but try not to yank it too hard. Allow the engine to reach top speed before using.
Fuel caps will have a small vent hole or holes to allow air into the tank, creating a vacuum that can make the engine difficult to start. Try loosening the cap slightly then see if you can start the engine.
Set the choke. You can open up this automatic choke by pressing the gas pedal all the way down and then raising it about halfway up before starting the engine.
Additional Tips
Following basic maintenance goes a long way toward preventing issues with small engines. Stabilize the fuel over winter. Change oil and plugs as specified. And keep air filters clean. Take care of your equipment and it will take care of you when spring rolls around.